EC 110 ELECTRONICS ENGINEERING WORKSHOP

Electronics engineering workshop

LIST OF EXPERIMENTS

1. Familiarization of electronic components

3. Familiarization of testing instruments and commonly used tools

4. Testing of electronic components

5. Interconnection method and soldering practice

6. Printed circuit board

7. Assembling of electronic circuit/system on general purpose pcb test and show the functioning

8. Familiarization of Electronic Systems

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EXPERIMENT NO:1

FAMILIARISATION OF ELECTRONIC COMPONENTS AIM To familiarize with various Electronic Components such as;  Passive Components  Active Components THEORY PASSIVECOMPONENTS The electronic components which are not capable of amplifying or processing an electrical signal are called passive components such as resistors, capacitors & inductors. However, in electronic circuits, these components are important as active components because without the aid of these components, the active devices cannot process the electrical signals. RESISTORS Resistors are the most commonly used of all electronic components, to the point where they are almost taken for granted.There are many different resistor types available with their principal job being to "resist" the flow of current through an electrical circuit, or to act as voltage droppers or voltage dividers. When used in DC circuits the voltage drop produced is measured across their terminals as the circuit current flows through them while in AC circuits the voltage and current are both in-phase producing 0o phase shift. Resistors produce a voltage drop across themselves when an electrical current flows through them because they obey Ohm‘s Law, and different values of resistance produces different values of current or voltage. There are many types of resistors and they are classified based on their particular characteristics and accuracy suiting certain areas of application, such as High Stability, High Voltage, High Current etc, or are used as general purpose resistors where their characteristics are less of a problem. Some of the common characteristics associated with the humble resistor are; Temperature Coefficient, Voltage Coefficient, Noise, Frequency Response, Power as well as Temperature Rating, Physical Size and Reliability. The unit of resistance, R is ohm and denoted by the Greek symbol ‗Ω‘ (omega). The schematic symbol of R is shown below;

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Carbon Composition Resistors

Carbon Composition Resistors are the cheap general purpose resistors. Their resistive element is manufactured from a mixture of finely ground carbon dust or graphite (similar to pencil lead) and a non-conducting ceramic (clay) powder to bind it all together. The ratio of carbon to ceramic determines the overall resistive value of the mixture and the higher this ratio is the lower the resistance. The mixture is then moulded into a cylindrical shape and metal wires or leads are attached to each end to provide the electrical connection before being coated with an outer insulating material and colour coded markings. CarbonComposite Resistors are low to medium power resistors with low inductance which makes them ideal for high frequency applications but they suffer from drawbacks like low stability, more noisy & high temperature co-efficient. Typical Specifications: o Available Range : 1Ω to 10MΩ o Tolerance Range : ±5% to ±20% o Wattage Range : 0.125 W to 2 W o Operating temperature : -55°C to 100°C o DC working voltage : up to 350V

Film Resistors

The category of "Film Resistor" consist of Metal Film, Carbon Film and Metal Oxide Film resistor types, which are generally made by depositing pure metals, such as nickel, or an oxide film, such as tin-oxide, onto an insulating ceramic rod or substrate. The resistive value of the resistor is controlled by increasing the desired thickness of the film

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Electronics engineering workshop and then by laser cutting a spiral helix groove type pattern into this film. This has the effect of increasing the conductive or resistive path. This method of manufacturing allows for much closer tolerance resistors (1% or less) as compared to the simpler carbon composition types. Metal Film Resistors have much better temperature stability than their carbon equivalents, lower noise and are generally better for high frequency or radio frequency applications. Metal Oxide Resistors have better, high surge current capability with a much higher temperature rating than the equivalent metal film resistors.

Another type of film resistor commonly known as a Thick Film Resistor is manufactured by depositing a much thicker conductive paste of CERamic and METal, called Cermet, onto an alumina ceramic substrate. Cermet resistors have similar properties of metal film resistors and are generally used for making small surface mount chip type resistors, multi-resistor networks in one package for PCB's and high frequency resistors. They have good temperature stability, low noise, and good voltage ratings but low surge current properties. Typical Specifications: o Available Range : 10Ω to 10MΩ o Tolerance Range : ±5% o Wattage Range : 0.25 W to 5 W o Operating temperature : -55°C to 125°C o DC working voltage : up to 750V 1.1.3 Wire-wound Resistors Wire-wound Resistors are made by winding a thin metal alloy wire (Nichrome) or similar wire onto an insulating ceramic former in the form of a spiral helix similar to the film resistors. These types of resistors are generally only available in very low ohmic high precision values due to the gauge of the wire and number of turns possible on the former making them ideal for use in measuring circuits and Whetstone bridge type applications. They are also able to handle much higher electrical currents than other resistors of the same ohmic value with power ratings in excess of 300 Watts. These high power resistors are moulded or pressed into an aluminium heat sink body with fins attached to increase their overall surface area to promote heat loss. The drawback of this type of

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Electronics engineering workshop resistor is that they are larger in size; cost‘s high and exhibits poor performance at high frequencies. Typical Specifications: o Available Range : 0.1Ω to 200KΩ o Tolerance Range : ±5% o Wattage Range : 3 W to 50 W o Operating temperature : -55°C to 275°C o DC working voltage : up to 500V 1.1.4 Variable Resistors They are usually used in electronic circuits to adjust values of currents & voltages. Potentiometers, presets and rheostats are examples of variable resistors. 1.1.4.1 Rheostat These are usually used in high power applications. It is constructed by winding a former with a Nickel-Copper wire in oxidation form. Former is usually 15cm – 30cm long, round shaped, made of ceramic & coated with vitreous enamel. A movable contact can be slided through an iron rod. Threading type terminals are provided for external connections. Potentiometer Another type of variable resistor commonly used is Potentiometers. They are available in the following ranges; 1K, 2.2K, 4.7K, 10K, 22K, 47K, 100K. Power rating of carbon track potentiometer ranges up to 2W. For high power applications wire wound potentiometers are used. Presets These types of variable resistors are used where the variation of resistance is not done frequently. Once the setting is made, it may be undisturbed. These types of resistors have a metallic wiper that can be moved with a screw driver. The tracks on which the wiper moves are carbonized or metalized ceramic.

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Capacitors A Capacitor is referred to as a condenser or a device one which stores energy in the form of an electrostatic field which produces a potential across its plates. Basically a capacitor consists of two parallel conductive plates that are not connected but are electrically separated either by air or by an insulating material called the Dielectric. On applying a voltage to these plates, current flows charging up the plates with electrons giving one plate a positive charge and the other plate an equal and opposite negative charge. This flow of electrons to the plates is known as the charging current and continues to flow until the voltage across the plates (and hence the capacitor) is equal to the applied voltage VC.The parallel plate capacitor is the simplest form of capacitor and its capacitance value is fixed by the equal area of the plates and the distance or separation between them. Altering any two of these values alters the value of its capacitance and this forms the basis of operation of the variable capacitors. Unlike other passive devices, there are several characteristics associated with a capacitor which are useful in selecting a capacitor for application & categorizing capacitors. Working Voltage The Working Voltage is the maximum continuous voltage that can be applied to the capacitor without failure during its working life. DC and AC values are usually not the same as the AC value refers to the r.m.s. value. Common working DC voltages are 10V, 16V, 25V, 35V, 63V, 100V, 160V, 250V, 400V and 1000V and are printed onto the body of the capacitor. Tolerance, (±%) This specifies how much the capacitor‘s actual values are nearer to the rated capacitance with coloured bands or letters. Capacitor‘s tolerance rating is expressed as a plus-or-minus value either in Picofarads (±pF) for low value capacitors generally less than 10pF or as a percentage (±%) for higher value capacitors generally higher than 10pF. The most common tolerance for capacitors is 5% or 10% but some electrolytic capacitors are rated as high as 20%. Leakage Current The dielectric used inside the capacitor is not a perfect insulator resulting in a very small current flowing or "leaking" through the dielectric when applied to a constant supply voltage. This small current flow in the region of micro amps (μA) is called the Leakage

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Current. This leakage current is a result of electrons physically making their way through the dielectric medium, around its edges or across the leads. The "leakage current" of a capacitor is sometimes called the "insulation resistance" and can be found using Ohm's law. Temperature Coefficient The Temperature Coefficient of a capacitor is the change in its capacitance with temperature expressed linearly as parts per million per degree centigrade (PPM/°C), or as a percent change over a specified temperature range. Polarization Polarization generally refers to the electrolytic type capacitors regarding to their connection. The majority are polarized types, that is the voltage connected to the capacitor terminals must have the correct polarity, i.e. +ve to +ve and -ve to -ve. Incorrect polarization can cause the oxide layer inside the capacitor to break down resulting in very large currents flowing through the device. The majority of electrolytic capacitors have their -ve terminal clearly marked with a black stripe or black arrows down the side to prevent any incorrect connection. Equivalent Series Resistance, (ESR) The Equivalent Series Resistance is the AC impedance of the capacitor when used at high frequencies and includes the resistance of the dielectric, plate and terminal leads. ESR acts like a resistor (less than 0.1Ω) in series with the capacitor and is frequency dependant. Film Capacitors Film Capacitors are the most commonly available type of capacitor, consisting of a relatively large family of capacitors with the difference being in their dielectric properties. These include polyester (Mylar), polystyrene, polypropylene, polycarbonate, metalized paper, teflon etc. Film type capacitors are available in capacitance ranges from 5pF to 100uF depending upon the actual type of capacitor and its voltage rating. Film capacitors are generally used for higher power and more precise applications.

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Ceramic Capacitors Ceramic Capacitors or Disc Capacitors as they are generally called are made by coating two sides by a small porcelain or ceramic disc with silver and are then stacked together to make a capacitor. For very low capacitance values a single ceramic disc of about 3-6mm is used. Ceramic capacitors have a high dielectric constant and are available so that relatively high capacitances can be obtained in a small physical size. Ceramic capacitors have values ranging from a few picofarads to one or two microfarads but their voltage ratings are generally quite low. Ceramic types of capacitors generally have a 3-digit code printed onto their body to identify their capacitance value. For example, 103 would indicate 10 x 103pF which is equivalent to 10,000 pF or0.01μF. Likewise, 104 would indicate 10 x 104pF which is equivalent to 100,000 pF or 0.1μF and so on. Electrolytic Capacitors Electrolytic Capacitors are generally used when very large capacitance values are required. Here instead of using a very thin metallic film layer for one of the electrodes, a semi-liquid electrolyte solution in the form of a jelly or paste is used which serves as the second electrode (usually the cathode). The dielectric is a very thin layer of oxide which is grown electro-chemically in production with the thickness of the film being less than ten microns. This insulating layer is so thin that it is possible to make large value capacitors of a small size. The majority of electrolytic types of capacitors are polarized, that is the voltage applied to the capacitor terminals must be of the correct polarity as an incorrect polarization will break down the insulating oxide layer and permanent damage may result. Electrolytic Capacitors are generally used in DC power supply circuits to help reduce the ripple voltage or for coupling and decoupling applications. Electrolytic's generally come in two basic forms; Aluminum Electrolytic and Tantalum Electrolytic capacitors.

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Aluminium Electrolytic Capacitors There are basically two types of Aluminium Electrolytic Capacitor, the plain foil type and the etched foil type. The thickness of the aluminium oxide film and high breakdown voltage give these capacitors very high capacitance values for their size. The etched foil type differs from the plain foil type in that the aluminium oxide on the anode and cathode foils has been chemically etched to increase its surface area and permittivity. This gives a smaller sized capacitor than a plain foil type of equivalent value. Despite, this type can't withstand high AC currents when compared to the plain type. Also their tolerance range is quite large up to 20%.

Etched foil electrolytic's are best used in coupling, DC blocking and by-pass circuits while plain foil types are better suited as smoothing capacitors in power supplies. Typical values of capacitance range from 1uF to 47000uF. AluminiumElectrolytic's are "polarized" devices so reversing the applied voltage on the leads will cause the insulating layer within the capacitor to be destroyed along with the capacitor, "so be aware". Tantalum Electrolytic Capacitors Tantalum Electrolytic Capacitors or Tantalum Beads, are available in both wet (foil) and dry (solid) electrolytic types with the dry (solid tantalum being the most common). Solid tantalums use manganese dioxide as their second terminal and are physically smaller than the equivalent aluminium capacitors. The dielectric properties of tantalum oxide is also much better than those of aluminium oxide This is because it gives lower leakage currents and better capacitance stability which makes them suitable for timing applications. Also tantalum capacitors although polarized, can tolerate when connected to a reverse voltage much more easily than the Aluminium types but are rated at much lower working voltages. Typical values of capacitance range from 47nF to 470μF.

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INDUCTORS The Inductor is another passive type electrical component designed to take advantage of this relationship (a wound coil is to use this magnetic flux to oppose or resist any changes in electrical current flowing through it) by producing a much stronger magnetic field than one that would be produced by a simple coil. Inductors are formed with wire tightly wrapped around a solid central core which can be either a straight cylindrical rod or a continuous loop or ring to concentrate their magnetic flux. The schematic symbol for a inductor is that of a coil of wire so therefore, a coil of wire can also be called an Inductor. Based on the type of core used they are categorized as air core inductor, iron core inductor, ferrite core inductor & powder core inductors. Variable inductors, transformers are a few categories of inductors that we commonly use. Transformer Its a device that works on the principle of mutual induction that is, it has 2 or more coils which are used to transfer electrical energy from one circuit to another at different voltages without changing the frequency. The most commonly used transformer is the power transformer. A power transformer is used to step up / step down the supply voltage & current. In step up, the number of turns in primary winding will be less than that in the secondary winding while in a step down transformer, the number of turns in the secondary will be less than that of primary winding. So a step up transformer is used for converting low voltage to high voltage and a step down transformer is used for converting a high voltage to a low voltage. Transformers are selected & categorized based on certain specifications such as; Voltage Rating It specifies the primary and secondary voltage of the transformer. It depends on the turns ratio of the windings and is usually expressed in Volts (V).

Current Rating It specifies the maximum current that the transformer winding can pass through to the load without any damage for the winding. It is expressed in Amperes (A).

Power Rating It specifies the maximum amount of power that can be delivered by the transformer continuously. It is usually expressed in Volts-Ampere (VA).

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Frequency Range It specifies the frequency range in which the transformer operates without any failure.

ACTIVE COMPONENTS SEMICONDUCTOR DIODES The term semiconductor diode refers to a two electrodes/ terminal device. A semiconductor diode is a one-way device, offering a low resistance when forward biased, and behaving almost as an open switch when reverse biased. A normal pn-junction diode consists of a p-type & n-type semiconductors sandwiched together. The p-side of the diode is always positive & is termed as anodewhile the n-side of the diode is always negative and termed as cathode. The circuit diagram of the diode is an arrowhead and bar where the arrowhead indicates the conventional direction of current flow under forward-biased

They are mainly manufactured of semiconductors such as Silicon &

Germanium. In case of Si, it can be seen that forward current(IF) remains very low until the forward voltage drop (VF) exceeds the barrier potential (VF≈0.7V). At VF greater than

0.7V, IF increases almost linearly. In case of Ge, VF changes to 0.3V. Since, the reverse currents are very much smaller than the forward current; the reverse characteristics are plotted on expanded current scales. For Si diode, IR is normally less than 100nA, and its almost independent of the reverse-bias voltage. For Ge diodes it falls in the micro-ampere range. Since, IR is the current due to minority charge carriers; it increases with increasing reverse-bias voltage. Also, the reverse breakdown voltage of Ge diode is substantially lower than that of Si diodes. Taking into account the lower forward voltage drop of Ge diode they has a distinct advantage but, the lower reverse current and higher reverse breakdown voltage of Si diodes makes more preferable in applications.

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Some Important Diode Parameters

 Peak Reverse Voltage (VR /VRRM) - Max. reverse voltage that can be applied across the diode.

 Steady State Forward current (IO/IF) – Max. current that can be passed continuously through the diode.

 Non-repetitive peak surge current (IFSM) – The maximum current that can be allowed to flow through the diode when it is switched ON first.

 Repetitive current (IFRM) – Peak current that can be repeated over again & again during the forward biased operation of a diode

 Static forward voltage drop (VF) – Max. forward voltage drop for a given forward current & device temperature.

 Continuous power dissipation (PD) – The max. power that the device can safely dissipate to the surrounding without the device getting damaged. 1N4001 to 1N4007, OA79, BY127, etc are some of the diodes that are popular in the market. Signal diodes, Rectifier diodes, LED‘s, zener diodes, Photo diodes, etc constitute the various categories of diodes.

Rectifier Diodes These diodes are used in rectification processes. These diodes are also called as low-power diodes. They are usually capable of passing a maximum forward current of 1A approx. They can also survive a reverse bias up to 500V and their reverse current is normally less than 1μA at 25°C. 1N4001 to 1N4007 Silicon diodes is an example of rectifier diodes.

They may be only posses a dimension of 0.3cm long & the cathode can be identified by a coloured band. These are generally intended for low-frequency applications.

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Signal Diodes The Signal Diode is a small non-linear semiconductor devices generally used in electronic circuits, where small currents or high frequencies are involved such as in radio, television and digital logic circuits or where a low value of capacitance is required between the terminals of the device. Signal diodes which are also sometimes known by their older name Point Contact or Glass Diode. They are physically very small in size and control small currents. Generally, a signal diode is encapsulated in glass to protect it and they generally have a red or black band at one end of their body to help identify which end is its Cathode terminal. In case of Ge signal diodes, they have a low reverse resistance value giving a lower forward volt drop across the junction, typically only about 0.2-0.3v, but have a higher forward resistance value because of their small junction area. While for Si signal diodes they have a very high value of reverse resistance and give a forward volt drop of about 0.6- 0.7v across the junction. They have fairly low values of forward resistance giving them high peak values of forward current and reverse voltage.The most widely used of all the glass encapsulated signal diode is 1N4148 Sisignal diode &OA79 Ge signal diode. Zener Diodes Zener Diodes or "Breakdown Diodes" as they are sometimes called, are basically the same as the standard junction diode but are specially made to have a low pre- determined Reverse Breakdown Voltage, called the "Zener Voltage" (VZ). In the forward direction it behaves just like a normal diode passing current, but when the reverse voltage applied to it exceeds the selected reverse breakdown voltage, reverse breakdown occurs in the diode & the current through the diode increases to the maximum circuit value, which is usually limited by a series resistor. There are mainly two mechanisms that results in this reverse breakdown in the reverse biased condition namely; Zener breakdown (on applying a high intensity electric field across a narrow depletion region, the electrons break away from their atoms thus converting the insulating depletion to conductor region that is, ionization by electric field)and Avalanche breakdown (if the depletion region is too wide, then in the presence of

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Electronics engineering workshop sufficient reverse bias voltage the electrons in the reverse saturation current collides with the electrons in the depletion region and thereby cause breakdown to occur that is, ionization by collision). Usually, zener breakdown occurs at reverse bias less than 5V and avalanche breakdown occurs at reverse voltage level above 5V.

TRANSISTORS A bipolar junction transistor (BJT) is simply a sandwich of one type of semiconductor material (n/p type) between two layers of the opposite type. Hence, there are basically two configurations of BJT namely; npn&pnptransistors. A small current at the central region terminal controls the much larger total current flow through the device.

Hence, a transistor can be used for current amplification & voltage amplification. From the above description, it is clear that a BJT is a three terminal device that is, the centre layer is known as base (B) and one of the outer layers is referred as emitter (E) and the other layer as collector (C). BC107, BF195, BC148, SL100, SK100, 2N3055 are some of commonly used bipolar transistors. The symbolic representations are shown below;

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FIELD EFFECT TRANSISTORS A field effect transistor (FET) is a unipolar, voltage controlled device which can be used for amplifiers & switching circuits, similar to a bipolar transistor. Unlike a BJT, a FET doesn‘t require an input current virtually which results in an extremely high input resistance; the most prominent advantage of FET over a BJT. There are two categories of FET namely; Junction FET (JFET) &Metal Oxide Semiconductor FET (MOSFET). These are further subdivided as p-channel&n-channel devices. In general, a FET has 4 terminals namely; Source(S),Drain(D), Gate(G) and Shield/Substrate(S). BFW10 & BFW11 are the popularly used n-channel JFETs.

UNIJUNCTION TRANSISTORS The unijunction transistor (UJT) consists of a bar of lightly doped n-type silicon with a block of p-type material on one side. Ohmic contacts are made at the opposite ends of the n-type bar, one of the terminals is termed as base1 (B1) and base2 (B2) of the transistor and the p-type rod is termed as emitter (E). Referring to the equivalent circuit,

the resistance of the n-type Si bar is represented by two resistors namely, rB1and rB2. The

summation of these two resistors provides the interbase resistance (RBB) of UJT. The diode (D1) represents the pn-junction between p-type and n-type semiconductor of the UJT. The prominent feature considered in application level is the negative resistance behaviour which is used in designing oscillators. They also play a key role in designing the firing/ triggering circuits for SCR‘s, in sweep wave generation, etc. 2N2646 is one of the most commonly used UJT.

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Cables Solid wire and cable are the oldest forms of electronic transmission media. This lesson covers three basic types, still in use in building networks, coaxial, unshielded twisted-pair, and fiber optic. Thin coaxial cable has a core of copper wire and is primarily used for peer-to-peer LANs due to its low bandwidth and problems with EMI (Electro- Magnetic Interference). Unshielded twisted-pair cable has twisted pairs of wires as the core and is divided into five categories, with category 5 used most commonly for building LANs. Fiber optic cable has a core made of glass and uses light pulses to transmit information across a network. Thin Coaxial Cable Early networks used coaxial cable to connect computers together. Many LANs were built with coaxial cable. It is often referred to as ThinNet. Coaxial cable has,  A core of copper wire surrounded by a layer of plastic.  A layer of metal mesh.  An outer protective plastic insulation sheath.

Unshielded Twisted-Pair Cable Unshielded twisted-pair cable is separated into five categories designated bythe TIA/EIA 568-A standard.  Category 1 is telephone cable.  Category 2 was used for token ring networks and is not recommended for Ethernet networks.

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 Categories 3 and 4 can be used with Ethernet networks, but suffer morefrom EMI than category 5. Category 3 cables typically have two twists perfoot. Category 4 cables have more twists per foot, but less than Category 5cables. The twisting of the wires in cables is to help prevent EMI (Electro-Magnetic Interference).  Category 5 cable is primarily used in LANs. The most typical connectorused with UTP is a RJ-45, which resembles a large telephone connectorRJ-11). This cable has a very high twist rate per foot.

Fiber-Optic Cable Fiber optic cable uses light pulses rather than electrical signals to transmitinformation across a network. The cable may be used over many miles becausethere is no electrical EMI (Electro-Magnetic Interference) and the bandwidth isvery high. Fiber optic cable is usually used for the backbone of a network.Since glass and plastic cores can be cracked or broken, installation requirescare. Special monitoring equipment is required to locate a break in the fiberoptic cable.

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Connectors

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. Connectors consist of plugs (male- ended) and jacks (female-ended). The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or devices. An adapter can be used to effectively bring together dissimilar connectors. There are hundreds of types of electrical connectors. Connectors may join two lengths of flexible copper wire or cable, or connect a wire or cable to an electrical terminal Electrical connectors are characterized by their pin out and physical construction, size, contact resistance, insulation between pins, ruggedness and resistance to vibration, resistance to entry of water or other contaminants, resistance to pressure, reliability, lifetime (number of connect/disconnect operations before failure), and ease of connecting and disconnecting.

They may be keyed to prevent insertion in the wrong orientation, connecting the wrong pins to each other, and have locking mechanisms to ensure that they are fully inserted and cannot work loose or fall out. Some connectors are designed such that certain pins make contact before others when inserted, and break first on disconnection; this protects circuits typically in connectors that apply power, e.g. connecting safety ground first, and sequencing connections properly in hot swapping applications.

It is usually desirable for a connector to be easy to identify visually, rapid to assemble, require only simple tooling, and be inexpensive. In some cases an equipment manufacturer might choose a connector specifically because it is not compatible with those from other sources, allowing control of what may be connected. No single connector has all the ideal properties; the proliferation of types is a reflection of differing requirements. Fretting is a common failure mode in electrical connectors that have not been specifically designed to prevent it.

Keying

Many connectors are keyed, with some mechanical component which prevents mating except with a correctly oriented matching connector. This can be used to prevent incorrect or damaging interconnections, either preventing pins from being damaged by being jammed in at the wrong angle or fitting into imperfectly fitting plugs, or to prevent damaging connections, such as plugging an audio cable into a power outlet. For

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Electronics engineering workshop instance, XLR connectors have a notch to ensure proper orientation, while Mini- DIN plugs have a plastic projection, which fits into a corresponding hole in the socket and prevent different connectors from being pushed together (they also have a notched metal skirt to provide secondary keying).

Plug and socket connectors

Plug and socket connectors are usually made up of a male plug (typically pin contacts) and a female receptacle (typically socket contacts), although hermaphroditic connectors exist, such as the original IBM token ring LAN connector. Plugs generally have one or more pins or prongs that are inserted into openings in the mating socket. The connection between the mating metal parts must be sufficiently tight to make a good electrical connection and complete the circuit. When working with multi-pin connectors, it is helpful to have a pinout diagram to identify the wire or circuit node connected to each pin.

Component and device connectors High-power transistor switch module with large screw connectors and small crimped-on "Fast-on" connectors.Electrical and electronic components and devices sometimes have plug and socket connectors or terminal blocks, but individual screw

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Electronics engineering workshop terminals and fast-on or quick-disconnect terminals are more common. Small components have bare lead wires for soldering.

Blade connector

A blade connector is a type of single wire connection using a flat conductive blade which is inserted into a blade receptacle. Usually both blade connector and blade receptacle have wires attached to them either through of the wire to the blade or crimping of the blade to the wire. In some cases the blade is an integral manufactured part of a component (such as a switch or a speaker unit), and a blade receptacle is pushed onto the blade to form a connection.

A common type of blade connector is the "Faston terminal". While Faston is a trademark of TE Connectivity (formerly Tyco Electronics), it has come into common usage. Faston connectors come in male and female types. They have been commonly used since the 1970s.

Ring and spade terminals

The connectors in the top row of the image are known as ring terminals and spade terminals (sometimes called fork or split ring terminals). Electrical contact is made by the flat surface of the ring or spade, while mechanically they are attached by passing a screw or bolt through them. The spade terminal form factor facilitates connections since the

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Electronics engineering workshop screw or bolt can be left partially screwed in as the spade terminal is removed or attached. Their sizes can be determined by the size of the conducting wire AWG and the screw/bolt diameter size designation.

P8C connector

8P8C is short for "eight positions, eight conductors", and so an 8P8C modular connector (plug or jack) is a modular connector with eight positions, all containing conductors. The connector is probably most famous for its use in Ethernet and widely used on CAT5 cables.

The 8P8C modular plugs and jacks look very similar to the plugs and jacks used for FCC's registered jack RJ45 variants, although the specified RJ45 socket is not compatible with 8P8C modular plug connectors. It neither uses all eight conductors (but only two of them for wires plus two for connecting a programming resistor) nor does it fit into 8P8C because the true RJ45 is "keyed".

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D-subminiature connectors

The D-subminiature electrical connector is commonly used for the RS-232 serial port on modems and IBM compatible computers. The D-subminiature connector is used in many different applications, for computers, telecommunications, and test and measurement instruments. A few examples are monitors (MGA, CGA, EGA), the Commodore 64, MSX, Apple II, Amiga, and Atari joysticks and mice, and game consoles such as Atari and Sega.

Another variant of D-subminiature are the Positronic D-subminiature connector which have PosiBand closed entry contact option, solid machined contacts, thermocouple contact options, crimp and PCB mount.And the Positronic Combo D-subminiature which have Large Surface Area (LSA) contact system that is for low contact resistance and saves energy, and sequential mating options.

USB connectors

The Universal Serial Bus is a serial bus standard to interface devices, founded in 1996. It is currently widely used among PCs, Apple Macintosh and many other devices. There are several types of USB connectors, and some have been added as the specification has progressed. The most commonly used is the (male) series "A" plug on peripherals, when the cable is fixed to the peripheral. If there is no cable fixed to the peripheral, the peripheral always needs to have a USB "B" socket. In this case a USB "A" plug to a USB

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"B" plug cable would be needed. USB "A" sockets are always used on the host PC and the USB "B" sockets on the peripherals. It is a 4-pin connector, surrounded by a shield. There are several other connectors in use, the mini-A, mini- B and mini-AB plug and socket (added in the On-The-Go Supplement to the USB 2.0 Specification).

Power connectors

Power connectors must protect people from accidental contact with energized conductors. Power connectors often include a safety ground connection as well as the power conductors. In larger sizes, these connectors must also safely contain any arc produced when an energized circuit is disconnected or may require interlocking to prevent opening a live circuit.

Socket, is the general term, in British English, but there are numerous common alternatives for household connectors, including power point,plug socket, wall socket, and wall plug.Receptacle and outlet are common in American English, for household connectors, sometimes with qualifiers such as wall outlet, electrical outlet and electrical receptacle.

Radio frequency connectors

Connectors used at radio frequencies must not change the impedance of the transmission line of which they are part, otherwise signal reflection and losses will result. A radio-frequency connector must not allow external signals into the circuit, and must prevent leakage of energy out of the circuit. At lower radio frequencies simple

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Electronics engineering workshop connectors can be used with success, but as the radio frequency increases, transmission line effects become more important, with small impedance variations from connectors causing the signal to reflect from the connector, rather than to pass through. At UHF and above, silver-plating of connectors is common to reduce losses. Common types of RF connectors are used for television receivers, two-way radio, certain Wi-Fi devices with removable antennas, and industrial or scientific measuring instruments using radio frequencies.

Relay

A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid- state relays. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

Simple electromechanical relay

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Fuse

In electronics and electrical engineering, a fuse is a type of low resistance resistor that acts as a sacrificial device to provide over current protection, of either the load or source circuit. It‘s essential component is a metal wire or strip that melts when too much current flows through it, interrupting the circuit that it connects. Short circuits, overloading, mismatched loads, or device failure are the prime reasons for excessive current. Fuses are an alternative to circuit breakers.

Electronic symbols for a fuse.

Switch A switch responds to an external force to mechanically change an electric signal. Switches are used to turn electric circuits ON and OFF and to switch electric circuits. There are many different types of switches. Based on their size, robustness, environmental resistance and other characteristics, they are divided into switches for industrial equipment and switches for consumer and commercial devices.

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Display A display device (commonly called a display or screen) is an output device for presentation of information in visualor tactile form (the latter used for example in tactile electronic displays for blind people). When the input information is supplied as an electrical signal, the display is called an electronic display Segment Display

Some displays can show only digits or alphanumeric characters. They are called segment displays, because they are composed of several segments that switch on and off to give appearance of desired glyph. The segments are usually single LEDs or liquid crystals. They are mostly used in digital watches and pocket calculators.

Heat Sink In electronic systems, a heat sink is a passive heat exchanger that cools a device by dissipating heat into the surrounding medium. In computers, heat sinks are used to

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Electronics engineering workshop cool central processing units or graphics processors. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light emitting diodes (LEDs), where the heat dissipation ability of the basic device is insufficient to moderate its temperature.

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EXPERIMENT NO: 2 INTRODUCTION TO BS/IEEE SYMBOLS & EDA TOOLS

AIM

To familiarize with various BS/IEE Symbols and EDA tools.

THEORY

In electronic circuits, there are many electronic symbols that are used to represent or identify a basic electronic or electrical device. They are mostly used to draw a circuit diagram and are standardized internationally by the IEEE standard (IEEE Std 315) and the British Standard (BS 3939).

Component Circuit Symbol Description

Used to connect one component to Wire Wire Circuit Symbol another.

One device may be connected to Wires Joined another through wires. This is represented by drawing ―blobs‖ on Wires Joined Circuit Symbol the point where they are shorted.

When circuits are drawn some wires may not touch others. This Unjoined can only be shown by bridging Wires them or by drawing them without

Wires Not Joined Circuit blobs. Symbol

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POWER SUPPLIES Component Circuit Symbol Description

Used to provide a supply for a Cell circuit.

Cell Circuit Symbol

A battery has more than a cell and is used for the same purpose. The smaller terminal is negative and Battery the larger one is positive. Abbreviated as ‗B‘.

Battery Circuit Symbol

DC Supply Used as a DC power supply, that DC Supply Circuit Symbol is, the current will always flow in one direction.

Used as AC power supply, that is, AC Supply the current will keep alternating directions.

Used in circuits where a probability of excessive current flows. The fuse will break the Fuse circuit if excessive current flows and saves the other devices from damage.

Used as an ac power supply. Consists of two coils, the primary and secondary that are linked together through an iron core. Transformer There is no physical connection between the two coils. The principle of mutual inductance is used to obtain power.

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Centre Tapped Transformer

Step Down Transformer

Step Up Transformer

Used in electronic circuits to represent the 0 volts of the power supply. It can also be defined as Earth/Ground the real earth , when it is applied in radio circuits and power Earth Circuit Symbol circuits.

RESISTOR Component Circuit Symbol Description

Resistor A resistor is used to restrict the Resistor Circuit Symbol amount of current flow through a device. Abbreviated as ‗R‘.

A rheostat is used to control the current flow with two contacts. Rheostat Applicable in controlling lamp Rheostat Circuit Symbol brightness, capacitor charge rate, etc.

A potentiometer is used to control the voltage flow and has three Potentiometer contacts. Have applications in changing a mechanical angle Potentiometer Circuit change to an electrical parameter.

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Symbol Abbreviated as ‗POT‘.

Presets are low cost variable resistors that are used to control the charge flow with the help of a Preset screw driver. Applications where Preset Circuit Symbol the resistance is determined only at the end of the circuit design. CAPACITOR Component Circuit Symbol Description

Capacitor is a device that is used to store electrical energy. It Capacitor consists of two metals plates that Capacitor Circuit Symbol are separated by a dielectric.. Abbreviated with the letter ‗C‘.

Capacitor – Capacitor can be used in a timer Polarized Capacitor-Polarised Circuit circuit by adding a resistor. Symbol

Used to vary the capacitance by turning the knob. A type of Variable variable capacitor is the trimmer Capacitor Variable Capacitor Circuit capacitor that is small in size. The Symbol notations are all the same.

DIODE Component Circuit Symbol Description

A diode is used to allow electric Diode current to flow in only one Diode Circuit Symbol direction. Abbreviated as ‗D‘.

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LED is used to emit light when a Light Emitting current is passed through the Diode (LED) LED Circuit Symbol device. It is abbreviated as LED.

After a breakdown voltage, the device allows current to flow in Zener Diode the reverse direction as well. It is Zener Diode Circuit Symbol abbreviated as ‗Z‘.

Photo Diode Photodiode works as a photo- Photo Diode Circuit Symbol detector and converts light into its corresponding voltage or current. TRANSISTOR Component Circuit Symbol Description

This is a transistor with a layer of P-doped semiconductor fixed between two layers of N- NPN doped semiconductors that act Transistor as the emitter and collector. Abbreviated as ‗Q‘. Transistor NPN Circuit Symbol

This is a transistor with a layer of N-doped semiconductor PNP Transistor fixed between two layers of P- doped semiconductors that act as the emitter and collector. Transistor PNP Circuit Symbol Abbreviated as ‗Q‘.

The working of a phototransistor is similar to that of a bipolar transistor with Phototransistor a difference that it converts light into its corresponding current. The phototransistor

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Phototransistor Circuit Symbol can also act as a photodiode if the emitter is not connected.

Like a transistor, a FET has three terminals, the Gate, Source and Drain. The device Field Effect has an electric field that Transistor controls the conductivity of a Field Effect Transistor Circuit channel of one type charge Symbol carrier in a semiconductor substance.

The Junction Field Effect Transistor (JFET) is the simplest type of FET with applications in Switching and voltage variable resistor. In an N-Channel N-channel JFET an N-type Junction FET silicon bar has two smaller pieces of P-type silicon n-channel Junction Field Effect material diffused on each sides Transistor (JFET) Circuit of its middle part, forming P- Symbol N junctions.

P-channel JFET is similar in construction to N-channel P-Channel JFET except that P-type Junction FET semiconductor base is sandwiched between two N- p-channel Junction Field Effect type junctions. In this case Transistor (FET) Circuit Symbol majority carriers are holes.

Abbreviated as MOSFET. MOSFET is a three Metal Oxide terminal device and is Semiconductor controlled by a gate bias. It is FET known for its low capacitance and low input impedance.

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The enhancement MOSFET structure has no channel formed during its construction. Voltage is applied to the gate, so as to develop a channel of Enhancement charge carriers so that a MOSFET current results when a voltage is applied across the drain- source terminals. Abbreviated e-MOSFET Circuit Symbol as e-MOSFET.

In the depletion-mode construction a channel is physically constructed and a current between drain and Depletion source is due to voltage MOSFET applied across the drain-source terminals. Abbreviated as d- d-MOSFET Circuit Symbol MOSFET.

METERS Component Circuit Symbol Description

Voltmeter Voltmeter is used to measure Voltmeter Circuit Symbol the voltage at a certain point in the circuit.

An Ammeter is used to Ammeter measure the current that passes through the circuit at a Ammeter Circuit Symbol particular point.

Ohmmeter

Ohmmeter Circuit Symbol Resistance of the circuit is measured using an Ohmmeter.

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An oscilloscope is used to Oscilloscope measure the voltage and time period of signals along with Oscilloscope Circuit Symbol their shape display.

SENSORS Component Circuit Symbol Description

It is abbreviated as LDR. Light Dependent Resistor is used to Light convert light into its corresponding Dependent resistance. Instead of directly Resistor measuring the light, it senses the (LDR) LDR Circuit Symbol heat content and converts it onto resistance.

Instead of directly measuring the light, a thermistor senses the heat Thermistor content and converts it into Thermistor Circuit Symbol resistance. Abbreviated as ‗TH‘.

SWITCHES Component Circuit Symbol Description

Push Switch This is an ordinary switch that Push Switch Circuit Symbol passes current only upon pressing.

The push to break switch is usually kept in the ON state Push to Break (closed). It turns to OFF state Switch Push to Break Switch Circuit (open) only when the switch is Symbol pressed.

Singe Pole Also known as the ON/OFF Single Throw switch. This switch allows the Switch flow of current only when it is

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On Off Switch (SPST) Circuit kept ON. Abbreviated as SPST. Symbol

Also known as the 2-way switch. It can be also called as an ON/OFF/ON switch as it has an Single Pole OFF position in the center. The Double Throw switch causes the flow of current Switch in two directions, depending on 2-Way Switch (SPDT) Circuit its position. It can be abbreviated Symbol as SPDT.

Abbreviated as DPST. Can also be called as a dual ON-OFF Double Pole switch. This is used to isolate Single Throw between the live and neutral Switch Dual On-Off Switch (DPST) connections in the main electrical Circuit Symbol line.

Double Pole Abbreviated as DPDT. The Double Throw switch uses a central OFF Switch position and is applied as DPDT Circuit Symbol reversing switch for motors.

Relay is abbreviated as ‗RY‘. This device can easily switch a 230 Volt AC mains circuit. It has Relay three switching stages called Normally Open (NO). Normally Relay Circuit Symbol Closed (NC), and Common (COM). AUDIO AND RADIO DEVICES Component Circuit Symbol Description

This device is used for converting Microphone sound to its corresponding electrical energy. Abbreviated as

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Microphone Circuit Symbol ‗MIC‘.

Earphone Does the reverse process of Earphone Circuit Symbol microphone and converts electrical energy into sound.

Does the same operation as an earphone, but converts an Loudspeaker amplified version of the electrical energy into its corresponding Loudspeaker Circuit Symbol sound.

Piezo- It is a transducer that converts Transducer PiezoTransducer Circuit electrical energy into sound. Symbol

Used to amplify a signal. It is mainly used to represent a whole Amplifier circuit rather than just one Amplifier Circuit Symbol component.

Aerial This device is used to Aerial Circuit Symbol transmit/receive signals. Abbreviated as ‗AE‘. OUTPUT DEVICES Component Circuit Symbol Description

Inductor is used to produce a magnetic field when a certain current is passed through a coil of wire. The Inductor wire is coiled on a soft iron core. Have applications in motors, and Inductor Circuit Symbol tank circuits. Abbreviated as ‗L‘.

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This device is used to convert electrical energy into mechanical Motor energy. Can be used as a generator as Motor Circuit Symbol well. Abbreviated as ‗M‘.

Used to produce a sound as the Bell output, according to the electrical Bell Circuit Symbol energy produced as the input.

It is used to produce an output sound Buzzer corresponding to the electrical Buzzer Circuit Symbol energy in the input.

Interpretation of electronic components

The electronic components are interpreted in various methods. Most of the passive components are interpreted using the color coding schemes and reading the codes printed on the body of the components. In case of active components we move on to the datasheet of the component.

Resistor color coding chart

An International resistor colour code scheme was developed many years ago as a simple and quick way of identifying a resistors value. It consists of coloured rings (in spectral order) whose meanings are illustrated below:

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SMD RESISTOR READING

CAPACITOR COLOR CODING CHART

Like resistors, small capacitors such as film or disk types conform to the BS1852 Standard where the colours are replaced by a letter or number coded system. The code consists of 2 or 3 numbers and an optional tolerance letter code. Where a two number code is used the value of the capacitor only is given in picofarads (ie. 47 = 47 pF). A three letter code consists of the two value digits and a multiplier much like a resistor colour code (ie. 471 = 47*10 = 47000pF = 47nF)

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The voltage rating of these capacitors are also marked by colour bands but the ratings are interpreted in different ways depending on the type of capacitor. The details is illustrated below;

In earlier days, the values of capacitance, voltage or tolerance are marked onto the body of the capacitors. However, when the value of the capacitance is of a decimal value problems arise with the marking of a "Decimal Point" as it could easily no be noticed resulting in a misreading of the actual value. Instead letters such as p (pico) or n (nano) are used in place of the decimal point to identify its position. For example, a capacitor can be labelled as, n47 = 0.47nF, 4n7 = 4.7nF or 47n = 47nF.

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Some Coded Capacitor value and their equivalents

Code (pF) (nF) (μF) Code (pF) (nF) (μF) 100 10 0.01 0.00001 472 4700 4.7 0.0047 150 15 0.015 0.000015 502 5000 5.0 0.005 220 22 0.022 0.000022 562 5600 5.6 0.0056 330 33 0.033 0.000033 682 6800 6.8 0.0068 470 47 0.047 0.000047 103 10000 10 0.01 101 100 0.1 0.0001 153 15000 15 0.015 121 120 0.12 0.00012 223 22000 22 0.022 131 130 0.13 0.00013 333 33000 33 0.033 151 150 0.15 0.00015 473 47000 47 0.047 181 180 0.18 0.00018 683 68000 68 0.068 221 220 0.22 0.00022 104 100000 100 0.1 331 330 0.33 0.00033 154 150000 150 0.15 471 470 0.47 0.00047 254 200000 200 0.2 561 560 0.56 0.00056 224 220000 220 0.22 681 680 0.68 0.00068 334 330000 330 0.33 751 750 0.75 0.00075 474 470000 470 0.47 821 820 0.82 0.00082 684 680000 680 0.68 102 1000 1.0 0.001 105 1000000 1000 1.0 152 1500 1.5 0.0015 155 1500000 1500 1.5 202 2000 2.0 0.002 205 2000000 2000 2.0 222 2200 2.2 0.0022 225 2200000 2200 2.2 332 3300 3.3 0.0033 335 3300000 3300 3.3

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SMD CAPACITORS

Generally the value is printed on them similar to the resistors.

INDUCTORS

Similar to the resistors and capacitors, the inductors mentioned for usage in electronic circuits are also standardised using colour coding schemes. In case of military purpose inductors a Silver banc will be present at the beginning of the bands. The chart below illustrates the details view of inductor colour coding;

WIRES Here either colouring or lettering scheme is used for illustrating the purpose for which a wire can be and is used. The details are mentioned below;

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Wire Lettering – The letters THHN, THWN, THW and XHHN represent the main insulation types of individual wires. These letters depict the following NEC requirements:.

 T – Thermoplastic insulation  H – Heat resistance  HH – High heat resistance (up to 194°F)  W – Suitable for wet locations  N – Nylon coating, resistant to damage by oil or gas  X – Synthetic polymer that is flame-resistant

Color Codes – Different colour wires serve different purposes, like:.  Black : Hot wire, for switches or outlets.  Red : Hot wire, for switch legs. Also for connecting wire between 2 hardwired smoke detectors.  Blue and Yellow : Hot wires, pulled in conduit. Blue for 3-4 way switch application, and yellow for switch legs to control fan, lights etc.  White : Always neutral.  Green and Bare Copper : Only for grounding. INTERPRETATION OF ACTIVE COMPONENTS Unlike passive components, the Part number is an essential part of the active component identification process.Depending on where the parts are made the part numbers will mean somethingdifferent. Theyrepresent information that is important to the way the device is used. Forexample, what material the device is made out of, applications it can beused for, and a series of number that distinguish that part from all others soone can find device specifications and parts that may be compatible with thepart that is being looked up.There are many systems in use such as the European based Pro-electron system, the American based JEDEC system and the Japanese based JIS system and Major manufacturersintroduce their own schemes as well 1.1 Pro-electron standard The European semiconductor standard Pro-Electro was set up in 1966 in Brussels, Belgium. In 1983 it was merged with the European Electronic Component Manufacturers Association (EECA) and since then operates as an agency of the EECA. This system uses the following format; Two letters, serial number, [suffix]

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The 1st letter specifies the semiconductor material A - Germanium

B - Silicon

C - Gallium Arsenide

R - Compound Materials

The 2nd letter specifies the type of device A - Diode, low power or signal B - Diode, variable capacitance C - Transistor, audio frequency low power D - Transistor, audio frequency power E - Diode, tunnel F - Transistor, high frequency low power G - Miscellaneous devices H - Diode, sensitive to magnetism K - Hall effect device L - Transistor, high frequency power N - Photo coupler P - Light detector Q - Light emitter R - Switching device, low power e.g. Thyristors, diac, UJT,etc S - Transistor, low power switching T - Switching device power, e.g. Thyristors, triac, etc U - Transistor, switching power W - Surface acoustic wave device X - Diode, multiplier, e.g. varactor Y - Diode, rectifying Z -Diode, voltage reference Serial Number - The serial number runs from 100-9999. Suffix - If a suffix is present then this indicates the gain group as below; A - Low gain B - Medium gain

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C - High gain For example, AC107 would be a Ge, Transistor used for low power audio frequency application.

1.2 Joint Electron Devices Engineering Council (JEDEC) The JEDEC Solid State Technology Association, formerly known as the Joint Electron Devices Engineering Council (JEDEC), is an independent semiconductor engineering trade organization and standardization body. Associated with the Electronic Industries Alliance (EIA), a trade association that represents all areas of the electronics industry in the United States, JEDEC has over 300 members, including some of the world's largest computer companies.This system has the following format; Digit, letter, serial number, [suffix] Digit-The first digit designates the amount of P-N junctions in the device. So a device starting with "2" would contain 2 P-N junctions and would most likely be either a transistor or a FET. Common part numbers are listed below; 1 - Diodes 2 - Bipolar transistors or Field Effect Transistors 3 - Double Gate MOSFETS, SCR's 4 - Opto Couplers Letter-The letter is always "N", and the remaining figures contain the device serial number. Serial Number -The serial number runs from 100 to 9999 and indicates nothing about the transistor. Suffix -If a suffix is present then this indicates the gain group as below; A - Low gain B - Medium gain C - High gain For example, 1N4001 would be a diode and 3N201 would be a double gate MOSFET.

1.3 Japanese Industrial Standard (JIS)

The Japanese Industrial Standard has the following format; Digit, two letters, serial number, [suffix] Digit -This indicates the amount of p-n junctions as in the JEDEC code.

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Letters -The letters indicate the intended application for the device according to the following code; SA - PNP HF transistor

SB - PNP AF transistor

SC - NPN HF transistor

SD - NPN AF transistor

SE - Diodes

SF - Thyristors

SG - Gunn devices

SH - UJT

SJ - P-channel FET/MOSFET

SK - N-channel FET/MOSFET

SM - Triac

SQ - LED

SR - Rectifier

SS - Signal diodes

ST - Diodes

SV - Varicaps

SZ - Zener diodes

Serial Number -The serial number runs from 10-9999.

Suffix -The (optional) suffix indicates that the type is approved for use by various Japanese organizations.

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Major Manufacturers Major manufacturers often produce their own code and numbering scheme for commercial reasons. The following abbreviations represent some of the larger semiconductor manufacturers; MJ - Motorola power, metal case MJE - Motorola power, plastic case MPS - Motorola low power, plastic case MRF - Motorola HF, VHF and microwave transistor TIP - Texas Instruments power transistor (plastic case) TIPL - TI planar power transistor TIS - TI small signal transistor (plastic case) Common examples include: TIP32A, MJE3055, ZTX302. Because of the late standardization of the European semiconductor devices many different codes were used by a several manufactures, the code their used was most of the time brand specified. Some examples are AEI/BTH (GT and S numbering), Mullard (OA, OC series, STC/Brimar (M, GD, JK and TK series), Ediswan ( EFT, XA, XB and XC series), GEC (EW, S and SX series), New Markert (V, NKT series) and so on.

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Typical Component Datasheets

Datasheet of Standard Recovery Rectifier Diodes1N4001 thru 1N4007

Features:-  Subminiature size  Axial Lead mounted rectifiers  Used in general purpose low-power applications  Approx. 0.4gram weight  Cathode indicated by polarity band

MAXIMUM RATINGS 1N40 1N40 1N40 1N40 1N40 1N40 1N40 Parameter Symbol 01 02 03 04 05 06 07 Peak Repetitive Reverse voltage V 1000 RRM 50V 100V 200V 400V 600V 800V DC Blocking VR V Voltage Non-Repetitive 1000 1200 Peak Reverse V 60V 120V 240V 480V 720V RSM V V Voltage RMS Reverse V 35V 70V 140V 280V 420V 560V 700V voltage R(RMS) Average Rectified I 1 Amp Forward Current O Non-Repetitive I 30 Amp (1 cycle) Peak Surge Current FSM Operating T / T -65OC - +175OC Temperature Range J stg

ELECTRICAL CHARACTERISTICS Parameter Symbol Typ. Max. Unit Maximum Instantaneous Forward Voltage V 0.93 1.1 Volts Drop F Maximum Full cycle Average forward V --- 0.8 Volts Voltage Drop F(AV)

Maximum Reverse Current IR 0.05 10 A Maximum Full-Cycle Average Reverse I --- 30 A Current R(AV)

Datasheet of ZenerDiodes1N746 thru 1N759 Features:-

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 Silicon planar power diodes  Tolerance 10%, suffix ‗A‘ for 5%  Color band indicates cathode end.

MAXIMUM RATINGS Parameter Symbol Value Unit

Power Dissipation PO 500 mW O Junction Temperature TJ 175 C O Storage Temperature Range TSTG -65 to 200 C

Forward Voltage VF 1.5 V

ELECTRICAL CHARACTERISTICS

Device VZ (V) IZT (mA) ZZR () IR (A) IR (A) IZRM/IZM TA = 25C TA = (mA) 150C 1N746 3.3 20 28 10 30 110 1N747 3.6 20 24 10 30 100 1N748 3.9 20 23 10 30 95 1N749 4.3 20 22 2 30 85 1N750 4.7 20 19 2 30 75 1N751 5.1 20 17 1 20 70 1N752 5.6 20 11 1 20 65 1N753 6.2 20 7 0.1 20 60 1N754 6.8 20 5 0.1 20 55 1N755 7.5 20 6 0.1 20 60 1N756 8.2 20 8 0.1 20 45 1N757 9.1 20 10 0.1 20 40 1N758 10.0 20 17 0.1 20 35 1N759 12.0 20 30 0.1 20 38

Datasheet of NPN General Purpose TransistorsBC 107A/ BC 107B/ BC 107C

Features:-

 Silicon planar epitaxial NPN transistors.  Suitable in driver stages, signal processing circuits,low noise amplification, switching & low noise input stages.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage (IE = 0) VCBO 50 V

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Collector Emitter Voltage (IB = 0) VCEO 45 V Emitter – Base Voltage (IC = 0) VEBO 6 V Collector Current (DC) IC 100 mA Peak Collector Current ICM 200 mA Peak Base Current IBM 200 mA Total Power Dissipation PTOT 0.3 W Operating Junction Temperature TJ 200 C ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit

Collector Base Breakdown Voltage (IE = 0) V(BR)CB 50 V O Collector Emitter Breakdown Voltage (IB = V(BR)CE 45 V 0) O Emitter – Base Breakdown Voltage (IC = 0) V(BR)EB 6 V O Collector Cut-off Current (IE = 0) ICBO 15 nA Collector Emitter Saturation Voltage (IC = VCE(sat) 70 250 mV 10mA, IB = 0.5mA)

Base Emitter Saturation Voltage (IC = VBE(sat) 750 mV 10mA, IB = 0.5mA)

Base Emitter On Voltage (IC = 2mA, VCE = VBE(ON) 550 650 700 mV 5V)

DC Current Gain (IC = 2mA, VCE = 5V) hFE 110 180 220 BC107A 200 290 450 BC107B

Small signal Current Gain (IC = 2mA, VCE hfe 250 = 5V) 300 BC107A BC107B

Collector Base Capacitance (IE = 0, VCB = CCBO 4 6 pF 10V)

Emitter Base Capacitance (IC = 0, VEB = CEBO 12 pF 0.5V)

Input Impedance (IC = 2mA, VCE = 5V) hie 4 K BC107A 4.8 K BC107B

Reverse Voltage Ratio (IC = 2mA, VCE = hre 2.2 x 5V) 10-4 BC107A 2.7 x BC107B 10-4

Output Admittance (IC = 2mA, VCE = 5V) hoe 30 S BC107A 26 S BC107B

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Datasheet of NPN Epitaxial Silicon TransistorsBC 547/550

Features:-

 Silicon epitaxial NPN transistors.  Suitable for low noise amplification switching applications.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage VCBO 50 V Collector Emitter Voltage VCEO 45 V Emitter – Base Voltage VEBO 6 V Collector Current (DC) IC 100 mA Collector Power Dissipation PC 500 mW Storage Temperature TSTG -65 to 150 C

Operating Junction Temperature TJ 150 C

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Collector Cut-off Current (I = 0, V = E CB I 15 nA 30V) CBO Collector Emitter Saturation Voltage VCE(sat) 90 250 mV (IC = 10mA, IB = 0.5mA) Base Emitter Saturation Voltage VBE(sat) 700 mV (IC = 10mA, IB = 0.5mA) Base Emitter On Voltage (I = 2mA, V C CE V 580 660 700 mV = 5V) BE(ON) DC Current Gain (I = 2mA, V = 5V) C CE 110 220 BC 547A/ BC 550A h 200 450 BC 547B/ BC 550B FE 420 800 BC547C/ BC 550C

Output Capacitance (IE = 0, VCB = 10V) Cob 3.5 6 pF Input Capacitance (IC = 0, VEB = 0.5V) Cib 9 pF Current gain Bandwidth Product fT 300 MHz

Datasheet of NPN Silicon TransistorsBC 194/195

Features:-

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 Suitable for IF & RF applications.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage VCBO 30 V Collector Emitter Voltage VCEO 20 V Emitter – Base Voltage VEBO 5 V Collector Current (DC) IC 30 mA Total Power Dissipation PD 250 mW

Storage Temperature TSTG -65 to 125 C

Operating Junction Temperature TJ 125 C

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit

Collector Base Breakdown Voltage BVCBO 30 V Collector Emitter Breakdown Voltage BVCEO 20 V Emitter – Base Breakdown Voltage BVEBO 5 V Base Emitter On Voltage (I = 1mA, V = C CE V 0.65 0.74 V 10V) BE(ON) DC Current Gain (I = 1mA, V = 10V) C CE 38 71 BF 195D h 71 110 BF 195C FE 110 200 BF 194B

Common Emitter Feedback Capacitance (IC Cre 0.95 pF = 1mA, VCE = 10V)

Current gain Bandwidth Product fT 260 MHz

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Datasheet of NPN Silicon Medium Power Transistors SL100

Features:-

 Suitable for general purpose medium power applications.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage VCBO 60 V Collector Emitter Voltage VCEO 50 V Emitter – Base Voltage VEBO 5 V Collector Current (DC) IC 500 mA Total Power Dissipation PD 800 mW Storage Temperature TSTG -65 to 200 C

Operating Junction Temperature TJ 200 C

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Max. Unit

Collector Base Breakdown Voltage BVCBO 60 V Collector Emitter Breakdown Voltage BVCEO 50 V Emitter – Base Breakdown Voltage BVEBO 5 V Collector Cut-off Current ICBO 50 nA Emitter Cut-off Current IEBO 25 nA Collector Emitter Saturation Voltage VCE(sat) 0.6 V Base Emitter Saturation Voltage VBE(sat) 1.3 V Output capacitance Cob 20 pF DC Current Gain (IC = 10mA, VCE = hFE 25 100 10V) 100 300 SL100 SL100B

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Datasheet of PNP Silicon Medium Power Transistors SK100

Features:-

 Suitable for general purpose medium power applications.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage VCBO 60 V Collector Emitter Voltage VCEO 50 V Emitter – Base Voltage VEBO 5 V Collector Current (DC) IC 500 mA Total Power Dissipation PD 800 mW Storage Temperature TSTG -65 to 200 C

Operating Junction Temperature TJ 200 C ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Max. Unit

Collector Base Breakdown Voltage BVCBO 60 V Collector Emitter Breakdown Voltage BVCEO 50 V Emitter – Base Breakdown Voltage BVEBO 5 V Collector Cut-off Current ICBO 50 nA Emitter Cut-off Current IEBO 25 nA Collector Emitter Saturation Voltage VCE(sat) 0.6 V Base Emitter Saturation Voltage VBE(sat) 1.3 V Output capacitance Cob 20 pF DC Current Gain (IC = 10mA, VCE = 10V) hFE 25 100 SL100 100 300 SL100B NB: Polarity of voltages & currents are complementary of SL100

Datasheet of PNP Silicon Power Transistors 2N3055

Features:-

 Silicon epitaxial-base planar NPN transistor.  Suitable for power switching circuits, high fidelity amplifiers, usage in series & shunt regulators.

MAXIMUM RATINGS Parameter Symbol Value Unit

Collector Base Voltage VCBO 100 V

Collector Emitter Voltage VCEO 60 V

Emitter – Base Voltage VEBO 7 V

Collector Current IC 15 A

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Base Current IB 7 A

Total Power Dissipation PD 115 W

Storage Temperature TSTG -65 to 200 C

Operating Junction Temperature TJ 200 C

ELECTRICAL CHARACTERISTICS Parameter Symb Min. Max. Unit ol

Collector Emitter Sustaining Voltage VCEO( 60 V sus) Collector Cut-off Current ICEO 0.7 mA Emitter Cut-off Current IEBO 5 mA Collector Emitter Saturation Voltage VCE(sa 0.6 V t) Base Emitter ON Voltage VBE(O 1.5 V N) Second Breakdown Collector Current with IS/B 2.87 A forward biased Base.

DC Current Gain (IC = 10mA, VCE = 10V) hFE 20 70

Small signal Current gain hfe 15 120 NB: Complementary power transistor MJ2955. Values of parameters are the same but the polarity gets reversed. Datasheet of Silicon PN Junction Transistors2N2646 / 2N2647 Features:-

 Low Peak Point Current & Emitter Reverse Current  Passivated Surface for Reliability and Uniformity  Used in pulse and timing circuits, sensing circuits and thyristor trigger circuits.

MAXIMUM RATINGS Parameter Symbol Value Unit

Power Dissipation PD 300 mW RMS Emitter Current IE(RMS) 50 mA Peak Pulse Current IE 2 A Emitter Reverse voltage VB2E 30 V Interbase voltage VB2B1 35 V Operating Temperature TJ -65 to 125 C

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Intrinsic Stand-off Ratio 0.56 0.63 0.72 2N2646  0.68 0.82 2N2647

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Interbase resistance rBB 4.7 7 9.1 K

Emitter Saturation voltage VEB1(sat) 3.5 V Interbase modulated current IB2(mod) 20 mA

Emitter reverse current IEB2O 0.005 12 A Peak point emitter current 1 5 A 2N2646 IP 1 2 A 2N2647 Valley point emitter current 4 6 mA 2N2646 I 18 V 8 10 mA 2N2647 Base 1 peak pulse voltage 3 5 V 2N2646 V OB1 6 7 V 2N2647

Datasheet of n-channel depletion – JFETBFW10/BFW11

Features:-  Suitable for VHF/UHF amplification process.

MAXIMUM RATINGS Parameter Symbol Value Unit

Drain Source voltage VDS 30 V Drain Gate voltage VDG 30 V Reverse Gate-source voltage VGSR -30 V Forward gate current IG 10 mA Total power dissipation PD 300 mW

Operation Temperature TJ -65 to 150 C

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Gate Source Breakdown Voltage BVGSS 30 V (IG = 10A)

Gate Source Cut-off voltage (VDS = 15V) 8 V V 2N2646 GS(off) 6 2N2647 Gate source voltage (V = 15V) DS 2 7.5 2N2646 V V GS 1.25 4 2N2647

Gate reverse current (VGS = 20V) IGSS 0.1 nA

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Drain Saturation Current (VDS = 15V) 8 20 I mA 2N2646 DSS 4 10 2N2647

Forward trans admittance (VDS = 15V) 3.5 6.5 Y mmho 2N2646 fs 3 6.5 2N2647 Output Admittance (V = 15V) DS 85 2N2646 Y mho os 50 2N2647

Input Capacitance (VDS = 15V) Ciss 5 pF Reverse transfer capacitance (V DS C 0.8 pF = 15V) rss Forward trans admittance (V = DS Y 3.2 mmho 15V) fs

Datasheet of plastic molded SCR2P4M/2P5M/2P6M

Features:-  Miniature size, easy to install.  Less holding current.  Used in various applications such as temperature control, speed control of miniature motors, lamp dimmer, battery charger, solid state static switches, etc.

MAXIMUM RATINGS Parameter Symbol Value Unit

Non repetitive Peak Reverse Voltage VRSM 500 V Non repetitive Peak Off State Voltage VDSM 500 V Repetitive Peak Reverse Voltage VRRM 400 V Repetitive Peak Off State Voltage VDRM 400 V On state Current IT(AV) 2 A Peak Gate power Dissipation PGM 0.5 W Average gate power dissipation PGM(AV) 0.1 W Peak Gate forward current IFGM 0.2 A Peak Gate reverse voltage VRGM 6 V

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit

Repetitive Peak Reverse Current IRRM 100 A

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Repetitive Peak Off-state Current IDRM 100 A

On state voltage VTM 2.2 V

Gate trigger current IGT 200 A

Gate trigger voltage VGT 0.8 V Gate non-trigger voltage VGD 0.2 V Critical rate of rise of Off-state dv/dt 10 V/S voltage

Holding Current IH 1 3 mA

Datasheet of Glass Passivated SCRTYN 204 ---- TYN 1004

Features:-  High On-State Current.  Highly stable, reliable & surge capable.  Used in power supplies with 400Hz with resistive load or inductive load.

MAXIMUM RATINGS Parameter Symbol Value Unit

RMS on-state current ITRSM 4 A Non repetitive surge Peak On State Current ITSM 60 A Repetitive Peak Reverse Voltage VRRM 200 V Repetitive Peak Off State Voltage VDRM 200 V On state Current IT(AV) 2.5 A

ELECTRICAL CHARACTERISTICS Symbo Parameter Min. Typ. Max. Unit l Repetitive Peak Reverse I 0.01 mA Current RRM Repetitive Peak Off-state I 0.01 mA Current DRM

On state voltage VTM 1.8 V Gate trigger current IGT 15 mA Gate trigger voltage VGT 1.5 V Gate non-trigger voltage VGD 0.2 V Critical rate of rise of Off-state dv/dt 200 V/S voltage

Holding Current IH 30 mA Critical rate of rise of on-state di/dt 100 A/S current

Datasheet of TIMER ICLM/NE/SA 555

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MAXIMUM RATINGS Parameter Symbol Value Unit

Supply Voltage VCC 16 V

Lead Temperature TLEAD 300 C

Total power dissipation PD 600 mW

Operating temperature Toperating -40 to 85 C ELECTRICAL CHARACTERISTICS Symbo Parameter Min. Typ. Max. Unit l

Supply Voltage VCC 4.5 16 V Supply Current ICC 3 6 15 mA Control Voltage VC 2.6 9 11 V Threshold Voltage VTH 3.33 10 V

Threshold Current ITH 0.1 0.25 A

Trigger Voltage VTR 1.1 5 5.6 V

Trigger Current ITR 0.01 2 A

Reset Voltage VRST 0.4 0.7 1 V Reset Current IRST 0.1 0.4 mA Low Output voltage VOL 0.06 0.25 V High Output voltage VOH 12.75 12.5 13.3 V Rise Time of Output tR 100 ns Fall Time of Output tF 100 ns Datasheet of General Purpose Op-Amp A741C/ A741I /A741M

MAXIMUM RATINGS Parameter Symbol Value Unit Supply Voltage 18 V V A741C CC 22

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A741I 22 A741M Differential input voltage 15 A741C V 30 V A741I ID 30 A741M Input voltage 15 A741C V 15 V A741I I 15 A741M

Voltage between offset null & -VCC 15 A741C 0.5 V A741I 0.5 A741M

Total power dissipation PD 500 mW -65 to Operating temperature T C operating 150

ELECTRICAL CHARACTERISTICS Parameter Symbol Min. Typ. Max. Unit Input offset voltage 1 6 A741C V mV IO 1 5 A741I/A741M Adjustable offset voltage range V 15 mV A741C/ A741I /A741M IO Input offset current I 20 200 nA A741C/ A741I /A741M IO Input bias current I 80 500 nA A741C/ A741I /A741M bias Common mode input voltage range VICR 12 13 V A741C/ A741I /A741M Symbo Parameter Min. Typ. Max. Unit l Max. peak output voltage swing V 12 13 14 V A741C/ A741I /A741M OP Large signal differential voltage amplification 20 200 A V/mV A741C D 50 200 A741I /A741M Input resistance r 0.3 2 M A741C/ A741I /A741M i

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Output resistance r 75  A741C/ A741I /A741M o Input capacitance C 1.4 pF A741C/ A741I /A741M i CMRR (Common Mode Rejection Ratio) CMRR 70 90 dB A741C/ A741I /A741M Supply voltage sensitivity K 30 150 V/V A741C/ A741I /A741M SVS Short circuit output current I 25 40 mA A741C/ A741I /A741M OS Supply current (No load) I 1.7 2.8 mA A741C/ A741I /A741M CC Power dissipation (without load) P 50 85 mW A741C/ A741I /A741M D Slew rate at unity gain SR 0.5 V/s A741C/ A741I /A741M

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INTRODUCTION TO EDA TOOL AND DRAWING SCHEMATIC

Electronic Design Automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. This is sometimes referred to as ECAD (electronic computer-aided design) or just CAD. These tools work together in a design flow that chip designers use to design and analyze entire semiconductor chips. Before EDA, integrated circuits were designed by hand, and manually laid out. The process was fundamentally graphic, with the translation from electronics to graphics done manually. By the mid-1970s, developers started to automate the design along with the drafting. The first placement and routing tools were developed. The next era began about the time of the publication of "Introduction to VLSI Systems" by Carver Mead and Lynn Conway in 1980. This ground breaking text advocated chip design with programming languages that compiled to silicon. The immediate result was a considerable increase in the complexity of the chips that could be designed, with improved access to design verification tools that used logic simulation. Although the languages and tools have evolved, this general approach of specifying the desired behavior in a textual programming language and letting the tools derive the detailed physical design remains the basis of digital IC design today. The earliest EDA tools were produced academically. One of the most famous was the "Berkeley VLSI Tools Tarball", a set of UNIX utilities used to design early VLSI systems and still Espresso heuristic logic minimizer and Magic are widely used. 1981 marks the beginning of EDA as an industry where the larger electronic companies, such as Hewlett Packard, Tektronix, and Intelpursued EDA tools internally. Current digital flows are extremely modular. The front ends produce standardized design descriptions that compile into invocations of "cells‖ without regard to the cell technology. Cells implement logic or other electronic functions using a particular integrated circuit technology. Fabricators generally provide libraries of components for their production processes, with simulation models that fit standard simulation tools. Analog EDA tools are far less modular, since many more functions are required, they interact more strongly, and the components are less ideal (in general). EDA tools for electronics has rapidly increased in importance with the continuous scaling of semiconductor technology.EDA tools are also used for programming design functionality into FPGAs.

Proteus is an ECAD tool for microprocessor simulation, schematic capture, and printed circuit board (PCB) design with many more features developed and marketed by Labcenter Electronics. Proteus PCB design combines the ISIS schematic capture and ARES PCB layout programs to provide a powerful, integrated and easy to use suite of tools for professional PCB Design. Its simplicity and user friendly design made it popular among electronics hobbyists. Proteus is commonly used for digital simulations such as

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Getting Started with Proteus ECAD Tool

In case of Proteus tool‘s versions below 8 the process to start was very simple since, ISIS Schematic Capture and ARES PCB Layout were two independent parts of the same tool. To initiate a schematic/ PCB layout design you have to just double click on the corresponding icons.

To save the projects in ISIS Schematic Capture and ARES PCB Layout we need to use the option File  Save Design and Save Layout respectively.

While we move on to the higher versions like Proteus 8 Professional and higher the steps are little different. From the Proteus 8 Professional version onwards all the facilities are linked together. The below steps describes the step-by-step procedure to get started with Proteus 8 Professional version;

1. Double click on the Proteus 8 Professional icon in the desktop or select the same for the Start Menu.

2. The Home page of the tool opens up. Select File  New Project

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3. Now the New Project Wizard pops up where you can enter the name of the project, location of saving the project. Also you can select the option either to start a project from scratch or to enhance the project from an existing development board project.

4. Once the selection is made you can click Next (here it‘s have considered New project). Then the next dialog box opens which asks you whether you need to draw a schematic. If you just need to a PCB layout only no need of drawing the schematic then you can click Next without making any changes. Once schematic creation is selected then the template size is selected (Generally DEFAULT).

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5. On clicking Next, the dialog box proceeds and asks whether you need to include PCB layout design for the project. Similar to the case of schematic here also you can make the required decision and proceed further. On selecting the PCB layout design addition then you can select an appropriate template (Generally DEFAULT).

6. Now the dialog box proceeds and prompts whether you need to add a firmware or not. The selection of firmware is normally selected when we need to simulate a microcontroller project, such that coding and compiling can be done using Proteus itself.

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7. Now the dialog box proceeds and displays the summary of the options included in the project and the locations in which they are saved.

8. Click on Finish, if the project creation was as per your wish or if you need to make any alterations go Back and make it and proceed again and click Finish.

Getting Started with ISIS Schematic Capture

Open the ‗ISIS Professional‘ from PROTEUS. This is the application where the simulations of the circuits can be tested. But the same file can be further processed to transform it into a layout. Layout is the final design which is needed in order to make the

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PCB of a circuit. To make the schematic, first we must have its raw design. For this, after installing Proteus, run ISIS/ISIS Professional hence the following window appears;

The main window consists of various parts, a brief description of each part is mentioned below;

1. Schematic Editor window / Editing Window:

This is the space used to draw the schematic. Blue box indicates the editable area, we must place/put the components inside it. Note that this window doesn‘t contain any scroll bar, you can use the preview window on the top left corner to change the schematic visual range. The size of the editable area can be changed by selecting the option Set Sheet size from the System Menu.

2. Preview window / Overview Window:

The space on the left side of the window aside of the mode selection toolbar. It performs separate functions namely in component mode and editor mode. When you are in the component mode, the list of components selected will be displayed and when we select a component, the preview of the element will be shown in the preview window. Once we enter to the editor mode and when the mouse focus falls on the principle diagram editor window that is, place the component into the schematic editor window or click the mouse in the Editing window, the preview window will display the entire schematic diagram as a thumbnail. The content of the current diagram will be denoted by a green box in the preview window. You can use the mouse to click on it to change the location of the green box, thereby changing the schematic visual range.

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3. Model Selection Toolbar (Mode Selector Toolbar): a. Main Modes:

1. Select elements/ components. (Selected by default) 2. Place the connection point 3. Place a label (Used in case of use of bus in schematic) 4. Place text 5. Drawing bus 6. Placing subcircuits 7. Enables instant editing component parameters ( first click on the icon and then click the element you want to modify ) b. Tools:

1. Terminal interface (terminals) – You can select VCC, ground, output, input and other interfaces by entering this mode. 2. Device Pin : for drawing pin 3. Emulation chart (graph) - Used while performing various analyzes, such as Noise Analysis, etc.

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4. Recorder 5. Signal generator. 6. Voltage Probe - Used along with simulation charts 7. Current probe - Used along with simulation charts 8. Virtual Instrument – Used for placing instruments like CRO, Logic Analyzer, etc. c. 2D graphics (2D Graphics):

1. Draw line 2. Draw box 3. Draw circle 4. Draw arc 5. Draw polygons 6. Draw text 7. Draw symbols 8. Paintings, origin, etc.

4. Component List (The Object Selector): This lists out the selected components while in Component mode, list out the various terminal interface available when you enter the Terminals mode, list out the various signal generators available when you enter the Generators mode, list out the various charts/graphs available when you enter the Graph mode and so on. For example , when you select Components mode from the mode selector tool bar and click the " P " button which opens a component selection dialog box, select an element and click on the " OK ". Then the device/component selected will be displayed in the list of elements, later you can use this element in the component list by entering to component mode and clicking on the element in the list. 5. Toolbars direction (Orientation Toolbar): a. Rotate :

The rotation angle can be an integer multiple of 90 .

b. Flip: Flip Horizontal and vertical flip. Right-click the component , and then click the corresponding rotation icon. 6. Simulation Toolbar

1. Run 2. Single-step operation 3. Pause 4. Stop 7. Selecting the components

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a. Click the "P" button in the Component List/Object Selector, then a Component dialog box appears 8.

b. In the Keywords box of the dialog box , enter the name of the component required Eg: ATMEGA16, then it produces the following results :

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8. Once you find the preview of the component arrives in the dialog box then you can Click OK, and close the dialog box , then the components listed in the list ATMEGA16. 9. Place all the required components and the component list gets updated like;

10. To place the place to the schematic area select the required component in the component list and left click in the schematic editor window, so that the component will be placed in the Schematic Editor window. Similarly place all the components to the schematic editor window.

11. To add Ground & VCC to the schematic select the terminals icon from the mode selector toolbar then the dialog displaying the available terminal points will appear;

12. Click on GROUND, and left-click in the schematic editor window, so that the "ground" will be placed into the Schematic Editor window. 13. While placing components pay attention to place them inside the blue box of work area. 14. To make connection just bring the cursor to the tip of the pins available on the components placed, then you can see the tip changes its icon shape from arrow to pencil. Click on that point and move the cursor to the destination node/pin tip and

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click again once you have reached the destination tip/node point. You can see that the cursor icon shape has re-transformed to arrow icon. By default, VSS, VDD, VEE don't need connections , the default VSS = 0V, VDD = 5V, VEE =-5V, GND = 0V To delete/move any connections or components, select edit icon for mode selector toolbar and click on the desired component/connections and perform the required action by pressing DELETE button/ drag the component/connections.

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EXPERIMENT NO:3

FAMILIARISATION OF TESTING INSTRUMENTS AND COMMONLY USED TOOLS

AIM To familiarize with various Electronics Laboratory instruments and tools. Laboratory instruments,  Cathode Ray Oscilloscope  Function Generator  Digital Multimeter  Power supply Tools  Soldering iron  De soldering pump  Pliers  Cutters  Wire strippers  Screw drivers  Tweezers  Crimping tool  Hot air soldering and de soldering station

THEORY Cathode Ray Oscilloscope (CRO) The CRO is an extremely useful and most versatile laboratory instrument used for studying wave shapes of alternating currents & voltages as well as for measurement of voltage, current, power and frequency; in fact, almost any quantity involves amplitude and waveforms. It allows the user to see the amplitude of electrical signals as a function of time on the CRT screen. In most applications, the graph shows how signals change over time: the vertical (Y) axis represents voltage and the horizontal (X) axis represents time. The display consists of a tube with an electron gun, x and y-deflection plates, and a phosphor screen which glows in response to an internal electron beam. In normal

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The compact, light weight model 3800 series oscilloscope has a wide frequency range of operation and offers many features;  Wide operating frequency range:3806:DC-60MHz, 3804:DC-40MHz,3802:DC- 25MHz

 High sensitivity: 1mV/div  Large size CRT: Large 6 inch CRT with internal graticule scale, hence easy to read waveforms.  Scale: Parallax-free waveforms due to CRT‘s internal graticule scale.  Alt Mag: (x1) normal and (x10-3806) and (x5-3804/3802) magnification and simultaneous display ability.  Alt Trig: Stabilized triggering can be achieved even with two unrelated signals.  TV synchronization: Stable TV signals can be displayed with the help of additional circuitry.

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 Auto focus: Focus deviation is automatically corrected.  Trigger Lock: Automatic synchronic state of the trigger circuit.  Component Tester (only for 3802 & 3804): Special circuit that tests the in & out individual/components without any additional power requirement. It shows Faults, component‘s value, characteristics of the component and even half dead components.

FRONT PANEL DESCRIPTION POWER SUPPLY & CRT (1) POWER SWITCH ON/OFF Verify line voltage; press power push-button to turn the power ON, if the switch is released, the power is turned OFF. (2) POWER LAMP This lamp lights when the power is ON.

(3) INTENSITYKNOB Turning this knob clockwise increases the brightness. Turn the knob fully clockwise prior to connecting power. (4) FOCUS KNOB MCET Pathanamthitta Page 76

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Adjusts the brightness to an appropriate level with the intensity control and then adjust the focus control until the trace is at its clearest level. Although automatic focus occurs, sometimes it may be slightly out and then readjust the focus. (5) TRACE ROTATION This knob is used to correct the horizontal trace when it becomes slanted w.r.t the horizontal scale, due to the effect of magnetic forces. (6) SCALE ILLUM KNOB This is used to adjust scale brightness. If turned clockwise, brightness gets increased. This feature is useful for operations in dark locations/ while taking pictures. (38)AC RECEPTACLE (Rear panel) This is the connector for AC power cable.

VERTICAL AXIS SECTION (30)CH 1 INPUT CONNECTOR A BNC connector is used for vertical input. Signal applied to this connector becomes the Y-signal in X-Y mode. (24)CH 2 INPUT CONNECTOR Same as above except that the signal applied becomes the X-signal in X-Y mode. (22)(29) AC-GND-DC SWITCH It selects the coupling method of the vertical amplifier. AC: The vertical input is connected through a capacitor and hence the DC component of the signal gets blocked and only AC component gets displayed. GND: Input of the vertical amplifier gets grounded. DC: Direct coupling takes place. Input signal including DC component gets displayed on the CRT.

(25) (33) Volts/Div SELECTOR SWITCH It‘s a step attenuator switch used to vary the vertical deflection sensitivity. It can be set to a position which displays the input signal at the most convenient height on the CRT. If a 10:1 probe is used, 10 times the height is calculated.

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(26) (32) Var KNOB This fine adjustment is used for varying the vertical axis deflection continuously. On complete counter clockwise turning the sensitivity gets reduced to <1/2.5 of the

VOLTS/DIV switch setting. Normally kept in full clockwise position. This knob is mainly used for comparing two waveforms and rise time measurements. (20) (36) x5 MAG BUTTONS On pressing this button, the vertical axis gain gets 5 times magnified and the maximum sensitivity of 1mV/div can be achieved. (23) (35) POSITION Used for moving CH1/ CH 2 trace up/ down on the CRT screen. (21) INVERT PUSH BUTTON SWITCH On pressing this switch the polarity of the input in CH 2 gets inverted. This function is useful in comparing two waveforms of different polarities, displaying the CH 1 & CH 2 difference waveforms using ADD. Vertical mode push buttons are used for selecting vertical axis operating mode. (34) CH 1 Signal applied to CH 1 gets displayed on the CRT screen. (28) CH 2 Signal applied to CH 2 gets displayed on the CRT screen. (34) (28) DUAL When both CH1 & CH 2 buttons are pressed, the signals applied to CH 1 & CH 2 gets displayed simultaneously on the CRT in either chopped/ alternate display. (31) ADD Displays the algebraic sum of CH 1 & CH 2 input voltages. The difference value can be displayed on pressing the CH 2 invert button. (40) CH 1 SIGNAL O/P CONNECTOR It provides a 20mV/Div replica of CH 1 input which can be used with a frequency counter.

HORIZONTAL AXIS SECTION (15) Time/Div SELECTOR SWITCH

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It selects the sweep speed from 0.1µs/div to 0.2s/div in 20 calibrated steps. (11) X-Y Displays the CH 1 & CH 2 inputs as an X, Y graph. Vertical deflection corresponds to CH 1 i/p & horizontal deflection corresponds to CH 2 i/p. The vertical position control (23) and Horizontal position control(14) positions the X,Y display vertically and horizontally on CRT. (12) SWEEP Var SWITCH On turning all the way clockwise Time/Div switch indicates the sweep and on all the way counterclockwise turning sweep indicates <1/2.5 the Time/Div setting. (14) HORIZONTAL POSITION Moves the trace horizontally. Used for measuring the waveform‘s time duration. (9) x5/x10 PUSH BUTTON On pressing, magnifies the trace by a factor of x5/x10. The sweep time becomes 1/10 or 1/5 of the value indicated on the Time/Div switch. For magnifying a portion of interest, move the portion of interest to the center graticule and the press the switch. (8) ALT MAG KNOB Displays the normal and magnified trace simultaneously on the CRT. TRIGGERING (18) TRIGGER SOURCE SELECTOR SWITCH Used for selecting the sweep trigger signal source; Int: Input to CH 1/ CH 2 becomes the trigger signal. CH 2: Input to CH 2 becomes the trigger signal. Line: Power line frequency becomes the trigger source. Ext: external signal connected to TRIG input acts as trigger. (19) Ext INPUT CONNECTOR It‘s the input terminal for external trigger signal. (17) TRIG LEVEL KNOB This control sets the amplitude point on the trigger waveform that starts the sweep. (10) SLOPE KNOB

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Selects the polarity of the slope of the trigger source waveform. To select (+) slope button is pushed out and for (-) slope button is pushed in. (16)TRIG MODE SWITCH Auto: Runs in auto sweep mode. A trace will be displayed in absence of input signal. On proper triggered condition a stationery waveform is displayed. Norm: A trace is displayed only on proper triggered condition or in presence of input signal. Normal sweep is used when the input signal‘s frequency is less than 25Hz. TV-H: Effective on setting TV trig mode. Used for synchronizing horizontal of TV signal. TV-V: Effective on setting TV trig mode. Used for vertical synchronizing of TV signal. (39) Z-AXIS INPUT CONNECTOR Used for intensity modulating the CRT screen. Since this is an integrated DC system, (+) signal reduces brightness and (-) signal increases brightness. (7) Cal 0.5V TERMINAL outputs a 0.5Vpp 1 KHz rectangular wave for calibrating probes. (27) GND TERMINAL It acts as the grounding terminal. (40) COMP. TEST Used to change from oscilloscope to component tester. Also X-Y switch (11) must be pushed and AC-GND-DC switches (22) (29) should be switched to GND position. (42) COMPONENT TEST IN Terminals to which components or lead wires connecting components under test are connected. SIGNAL CONNECTION We make use of probes for measuring high frequency signals since the input signals are reduced to 1/10 of their value, this is unsuitable in case of low signals. For measurement accuracy the probe has to be calibrated.

MEASURING PROCEDURES

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Measuring DC Voltage Set the AC-GND-DC switch to GND, and position the zero level to convenient position on the screen. Set Volts/Div to appropriate setting and then set AC-GND-DC to DC. Then a straight line trace gets deflected. The DC voltage can be obtained by multiplying the amount of divisions the line deflects by the Volts/Div value. Measuring AC Voltage Follow the same procedure as above except change the AC-GND-DC switch position to AC position. Frequency and Time Measurement Calculate the divisions on the screen between two adjacent +/- peaks of the displayed waveform. Then multiply the value with the sweep time value obtained from the position of Time/Div knob. Time Difference Measurement The following procedures are followed; A To find the time CH 2 is delayed w.r.t CH 1 set the trigger signal source to Int. B To find the time CH 1 is delayed w.r.t CH 2 set the trigger signal source to CH 2.

C Delay time = (No. of divisions from the rising edge of the trigger source to rising edge of delayed signal)*Time/Div setting. Component Test Push X-Y switch for X-Y mode and set both AC-GND-DC switches to GND position as well as set the VOLTS/DIV knob of CH 1 to 5V/DIV, CH2 to 2V/DIV, then push the COMP. TEST switch. Components can be directly hooked to the COMP.TEST IN terminals or through lead wires.

Function Generator(FG) It is a very useful instrument for every test requirement. This is very convenient for quick operation with minimum effort in instrument setting. It can be used to test the frequency response of amplifiers, attenuators, filters, tec. The DC offset facility is very much useful whenever it is required to provide some biasing while coupling the signal.

APLAB 2011A Device Features:

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 Frequency Range : 1Hz- 2MHz in 6 decade ranges.  Output waveforms : Sine, triangle, balanced square, +ve square, -ve square, variable duty cycle pulse & variable slope ramp.  Sine Distortion : <3%  Attenuation : 0 dB, 20 dB, 40 dB, 60 dB  Pulse duty cycle : 10%-90% variable  Frequency counter range: 10Hz – 2MHz  D.C Offset : ±7.5V±5%, ±3.75V±5%

FRONT PANEL DESCRIPTION (1) EXT IN : This is a BNC receptacle for external input signal. (2) MODE : This switch selects the frequency display mode. (3) DISPLAY : This 4 digit 7 segment display indicates the frequency of selected signal. (4) LEDs : These LEDs indicate the frequency unit (Hz, KHz, & MHz) (5) GATE LED : This LED glows during measurement. (6) RANGE : Selects one of the six frequency ranges & corresponding range‘s LED glows. (7) FUNCTION : The output waveform is selected by this switch & corr. LED glows. (8) DC OFFSET : This is a two position switch. In ON condition, it offsets the selected waveform in conjunction with the variable control. (9) SYMMETRY : This is a two position switch. In ON condition, the duty cycle of the

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selected waveform can be varied by symmetry control. (10) FREQUENCY: This is continuously variable frequency control coarse & fine. (11) LEVEL : This is a continuously variable level control (12) ATTENUATOR : This is a 4 position rotary switch and attenuates o/p by 20, 40 & 60dB. (13) OUTPUT : This is a BNC connector for function output. SCIENTECH 10 MHz Generator Device Features:  Frequency Range : 1Hz- 10MHz (Sinewave). 1Hz-2MHz (all other signals)  Output waveforms : Sine, Square, Triangle, Ramp, Pulse.  Sine Distortion : 1.5%(2MHz), 2% (10MHz)  Attenuation : -20 dB, -40dB  Pulse duty cycle : 15%-85% variable  D.C Offset : ±5V adjustable.  Modulation : AM Standard, AM Balance, FM, ASK, FSK & PWM.

FRONT PANEL DESCRIPTION (1) POWER : Push button switch to supply power to the instrument. (2) DISPLAY : Digital 7 segment LED displays the 4-digit frequency output. (3) FREQUENCY : 7 position push button switch, selects frequency from 10Hz-10MHz. (4) FUNCTION : 5 position push button switch, selects desired function output. (5) MODULATION I : 5 position push button switch, selects the modulation. (6) MODULATION II: 4 position push button switch, selects the type of modulation.

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(7) OUTPUT : BNC connector terminal for taking output from function generator. (8) SWEEP RATE : It is used to vary internal sweep. (9) DUTY CYCLE : Used if pulse function is selected. Varies from 15% - 85%. (10) FREQ. VAR : Varies the output frequency in conjunction with (3). (11) AMPLITUDE Var: Helps to vary the output level in conjunction to attenuators. (12) DC OFFSET : This control provides DC offset. An approx. of ±5V DC can be superimposed. In case if DC offset is not required keep it OFF. (13) ATTENUATOR: A combination of 20dB & 40dB is available. Pressing both at same provides an attenuation of 60dB. (14) MODULATION IN FOR MODULATION I: This BNC terminal is provided for feeding modulating signal. Maximum input level is limited to 2Vpp. (15) MODULATION IN FOR MODULATION II: This BNC terminal is provided for feeding modulating signal. Maximum input level is limited to 2Vpp.

Digital Multimeter (DMM) A multimeter or a multitester, is known as a VOM (Volt-Ohm meter). It is an electronic measuring instrument that combines several measurement functions in one unit. A typical multimeter includes features such as the ability to measure voltage, current and resistance. Multimeters are of two types; Analog multimeters (AMM) and Digital multimeters (DMM /DVOM.) Analog multimeters are usually based on a microammeter whose pointer moves over a scale calibration for all the different measurements that can be made while digital multimeters usually display digits, with display bar of a length proportional to the quantity measured.

A multimeter can be a hand-held device useful for basic fault finding and field service work or a bench instrument which can measure with a very high degree of accuracy. They can be used to troubleshoot electrical problems in a wide array of industrial and household devices such as electronic equipment, motor controls, domestic appliances, power supplies, and wiring systems. Since, nowadays we deal with DMM commonly, a brief description on a commonly used DMM and its functions are described below;

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MECO Model:603 Device Features:  Display · 3 ½ digit liquid crystal display (LCD) with a maximum reading of 1999.  Polarity · Automatic, (-) negative polarity indication.  Zero adjustment · Automatic  Over range indication · Highest digit of(1) or (-1) is displayed at MSD  Low battery · ―(B)‖ is displayed when the battery voltage drops below the operating voltage  Measurement rate · 3 measurements per second, nominal  Operating conditions · 0°C to + 50°C at < 75% RH  Storage conditions · -20°C to + 60°C, 0-80% RH with battery removed.  Accuracy · Accuracy specifications at 23 ± 5°C, less than 75% RH  Power Supply · Single, standard 9-volt battery.  Battery life (typical) · 200 hours.

1.2 ELECTRICAL SPECIFICATIONS Accuracies are ± (% reading plus number of digits) at 23 ± 5°C, and humidity of less than 75% RH. DC VOLTAGE Ranges : 200mV, 2V, 20V, 200V, 1000V Accuracy : ±(0.5%rdg + 1dgt) on all ranges Resolution : 100µV to 1V Input Impedance : 10MV Overload Protection : 500V DC/350VAC for 15 sec. on 200mV range, 1200V DC/800V AC on all other ranges. AC VOLTAGE (50-500Hz) Ranges : 200mV, 2V, 20V, 200V, 750V Accuracy : ± (1% rdg + 4 dgt) on all ranges except ±(1.5% rdg + 4 dgt) on 750V MCET Pathanamthitta Page 85

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Resolution : 100µV to 1V Input Impedance : 10MΩ

Overload Protection : 500V DC/350VAC for 15 sec. on 200mVrange, 1200V DC/800V AC on all other ranges. DC CURRENT Ranges : 200mA, 2mA, 20mA, 200mA, 20A (In 20A range maximum measuring time ≤ 30s with an interval of 5 minutes) Accuracy : ± (1% rdg + 1 dgt) on all ranges except ±(2% rdg + 3 dgt) on 20A range Resolution : 100nA to 10mA Voltage Burden : 325mV except, 1.4V max. on 20A range Overload Protection : 0.8A/250V FUSED. on all ranges except 24A unfused for 30 sec. on 20A range AC CURRENT (50-500Hz) Ranges : 200mA, 2mA, 20mA, 200mA, 20A (In 20A range maximum measuring time ≤ 30s with an interval of 5 minutes) Accuracy : ± (1.2% rdg + 4 dgt) on all ranges except ±(2% rdg +4 dgt) on 20A range Resolution : 100nA to 10mA Voltage Burden : 325mV except, 1.4V max. on 20A range Overload Protection : 0.8A/250V FUSED on all ranges except 24A unfused for 30 sec. on 20A range RESISTANCE Ranges : 200Ω, 2KΩ, 20KΩ, 200KΩ, 2000KΩ, 20MΩ, 200MΩ Accuracy : ± (0.8% rdg + 1dgt) on all ranges except ± (1% rdg + 3 dgt) on 200Ω ± (3% rdg + 3 dgt) on 20MΩ ± (5% rdg + 10 dgt) on 200MΩ Resolution : 100mΩ to 100KΩ Overload Protection : 500V DC/AC Test Voltage : 200Ω, 200MΩ; 3.2V max; other ranges 0.3V max.

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CONTINUITY BEEPER Threshold : 100V approx. Response Time : 100mS hFE TEST Base DC Current : 10 mA

VCE : 2.8 ± 0.4V

Range : 0 To 1000 DIODE TEST Test Current : 1.0 ± 0.6Ma Test Voltage : 3.2V max. MEASURING PROCEDURES Voltage Measurement 1. Connect red test lead to ―V-Ω‖ input terminal and black test lead to ―COM‖ input terminal. 2. Set Function/Range switch to desired voltage type (DC or AC) and range. If magnitude of voltage is not known, set switch to the highest range and reduce until a satisfactory reading is obtained. 3. Turn off power to the device or circuit being tested and discharge all capacitors. 4. Connect test leads to the device or circuit being measured. 5. Turn on power to the device or circuit being measured. Voltage value will appear on the digital display along with the voltage polarity. 6. Turn off power to the device or circuit being tested and discharge all capacitors prior to disconnecting test leads.

Current Measurement 1. Connect red test lead to the ―mA‖ input terminal for current measurements up to 200mA. Connect black lead to the COM input terminal. 2. Set Function/Range switch to desired current type (DC or AC) and range. If magnitude of current is not known, set switch to the highest range and reduce until a satisfactory reading is obtained. 3. Turn off power to the device or circuit being tested and discharge all capacitors.

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4. Open the circuit in which current is to be measured. Now securely connect test leads in series with the load in which current is to be measured. 5. Turn on power to the device or circuit being tested. 6. Read current value on digital display. 7. Turn off all power to the device or circuit being tested and discharge all capacitors. 8. Disconnect test leads from circuit and reconnect circuit that was being tested. 9. For current measurement of 200mA or greater, connect the red test lead to ―20 A‖ input terminal & black test lest lead to the ―COM‖ input terminal. If the resistance being measured is part of a circuit, turn off power to the circuit and discharge all capacitors. Resistance Measurements 1. Connect red test lead to V-Ω input terminal and black test lead to COM input terminal. 2. Set Function/Range switch to desired V position. If magnitude of resistance is not known, set the switch to highest range and reduce until a satisfactory reading is obtained. 3. If the resistance being measured is part of a circuit, turn off power to the circuit and discharge all capacitors. 4. Connect test leads to the device or circuit being measured. When measuring high resistance, be sure not to contact adjacent points even if insulated, because some insulators have a relatively low insulation resistance, causing the measured resistance to be lower than the actual resistance. 5. Read resistance value on digital display. If a high resistance value is shunted by a large value of capacitance, allow digits to stabilize. Diode Tests 1. Connect red test lead to V-Ω input terminal and black test lead to COM input terminal. 2. Set Function/Range switch to the diode test position. 3. If the semiconductor junction being measured is part of to a circuit, turn off power to the circuit and discharge all capacitors. 4. Connect test leads to the device. 5. Read forward voltage drop value on digital display. 6. If the digital display reads over range (1) reverse the lead connections. The placement of the test leads when the forward reading is displayed indicates the orientation of the diode. The red lead is positive and the black lead is negative. if over range (1) is displayed with both lead connections, the junction is open. If a low-reading (less than 1,000) is obtained with both lead connections, the junction is shorted internally or (if junction is measured in

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Electronics engineering workshop a circuit) the junction is shunted by a resistance less than 1KV. In the latter case the junction must be disconnected from the circuit in order to verify its operation. Transistor Junction Tests 1. Bipolar transistors can be tested in the same manner as diode, junctions formed between the base and emitter and the base and collector of the transistor. Measurement between the collector and emitter also should be made to determine if a short is present.

Transistor hFE Measurements

1. Transistor must be out of circuit. Set the function/range switch to the hFE position. 2. Plug the emitter, base and collector leads of the transistor into the correct holes in either the NPN or the PNP transistor test socket, whichever is appropriate for the transistor being checked. Read the hFE (beta, or DC current gain) in the display. Continuity Measurements 1. Set the selectors switch to the ))) position. 2. Continuity between probe tips will be indicated by an audible beep when resistance is below 100Ω. TROUBLESHOOTING If there appears to be a malfunction during the operation of the meter, the following steps should be performed in order to isolate the cause of the problem: 1. Check the battery. 2. Review the operating instructions for possible mistakes in operating procedure. 3. Inspect and test the Test Probes for a broken or intermittent connection. 4. Inspect and test the fuse. If it is necessary to replace the fuse, be sure to install one of the proper current ratings.

DC-Power supply

The standard power supply you will use for most of your experiments is the ―power brick‖ sitting on your desk. This power supply is plugged into the connector on the breadboard platform. The wires coming out of the back end of the breadboard connector are shown in Figure . GROUND is a direct connection to the Earth through the ground terminal on the three-prong wall plug. COM stands for Common Ground. It is the reference point from which the other voltages (+5V, ±12V) are measured. COM is a ―floating‖ reference point. ―Floating‖ means it is not connected to Earth ground. All four terminals (+5V, ±12V, and COM) are isolated by a transformer, whose secondary

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Electronics engineering workshop windings power the circuitry that generates the output voltages. In fact, COM can be biased by a different power supply to any potential (up to 30V or so) and the three output voltages will likewise follow. The key thing to note is that the output voltages are relative to the floating COM terminal and not to the GND terminal. Thus, for all the labs it is recommended to connect the COM terminal to the GND terminal to ensure that all supply voltages generated by the ―power brick‖ are referenced to GND. Each voltage from the DC power brick (+5V, ±12V) is sent through a separate fuse on the breadboard mount. Make sure you only make connections to the supply voltage after the fuse. In the case of a wiring error, the fuse will blow, thus saving the power supply from possible damage. We do not provide an unlimited supply of replacement fuses. Please check your circuits very carefully before connecting to power!

DC-Power supply

Tunable voltage/current source The HP E3616A is a tunable voltage or current source.There are two knobs: Voltage and Current. These are used to adjust the constant voltage output by the device or the constant current output by the device. There are little green LEDs (CV and CC) near the display which indicate if the power supply is voltage or current limited, if it operates in voltage or current mode. For constant voltage mode, the current knob must be turned to a setting above any that need be supplied and then the voltage knob is set for the desired voltage. For constant current mode, the voltage knob must be turned to a setting above any that need be supplied and then the current knob is set for the desired current. The potential at the red terminal is always above that at the black terminal by the amount shown on the readout, but this potential difference is, like the power pack, floating. If the black terminal is wired to the green ground the red terminal will be at the potential given on the readout. If the red terminal is wired to the ground, the black terminal will be at a potential equal to the negative of the readout. The supplies may already have the black terminal grounded

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(with an easy to miss wire between them) for using the red terminal as a positive supply voltage.

Tunable voltage/current supply, also called the HP power supply. Soldering Iron A soldering iron is a hand tool used in soldering. It supplies heat to melt solder so that it can flow into the joint between two workpieces. A soldering iron is composed of a heated metal tip and an insulated handle. Heating is often achieved electrically, by passing an electric current (supplied through an electrical cord or battery cables) through a resistive heating element. Cordless irons can be heated by combustion of gas stored in a small tank, often using a catalytic heater rather than a flame. Simple irons less commonly used than in the past were simply a large copper bit on a handle, heated in a flame. Soldering irons are most often used for installation, repairs, and limited production work in electronics assembly. High-volume production lines use other soldering methods. Large irons may be used for soldering joints in sheet metal objects. Less common uses include pyrography (burning designs into wood) and plastic welding.

Electric soldering iron

De soldering pump A de soldering pump, colloquially known as a solder sucker, is a manually- operated device which is used to remove solder from a printed circuit board. There are two types: the plunger style and bulbstyle. (An electrically-operated pump for this purpose would usually be called a vacuum pump.) The plunger type has a cylinder with a spring- loaded piston which is pushed down and locks into place. When triggered by pressing a button, the piston springs up, creating suction that sucks the solder off the soldered

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Electronics engineering workshop connection. The bulb type creates suction by squeezing and releasing a rubber bulb. The pump is applied to a heated solder connection, then operated to suck the solder away.

A typical spring-loaded solder sucker

Soldering and De soldering stations

A soldering station, invariably temperature-controlled, consists of an electrical power supply, control circuitry with provision for user adjustment of temperature and display, and a soldering iron or soldering head with a tip temperature sensor. The station will normally have a stand for the hot iron when not in use, and a wet sponge for cleaning. It is most commonly used for soldering electronic components. Other functions may be combined; for example a rework station, mainly for surface-mount components may have a hot air gun, vacuum pickup tool, and a soldering head; a de-soldering station will have a de-soldering head with vacuum pump for de-solderingthrough hole components, and a soldering iron head.

Temperature-controlled soldering station Pliers Pliers arehand tools used to hold objects firmly, possibly developed from tongs used to handle hot metal in Bronze Age Europe. They are also useful for bending and compressing a wide range of materials.

Flat-nose pliers Wire stripper A simple manual wire stripper is a pair of opposing blades much like scissors or wire cutters. The addition of a center notch makes it easier to cut the insulation without cutting the wire. This type of wire stripper is used by rotating it around the insulation while

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Electronics engineering workshop applying pressure in order to make a cut around the insulation. Since the insulation is not bonded to the wire, it then pulls easily off the end.

A wire stripper Screw driver A screwdriver is a tool, manual or powered, for turning (driving or removing) screws. A typical simple screwdriver has a handle and a shaft, and a tip that the user inserts into the screw head to turn it. The shaft is usually made of tough steel to resist bending or twisting.

Tweezers Tweezers are tools used for picking up objects too small to be easily handled with the human hands.Most of the electronic grade tweezers are coated with a colored epoxy resin which is insulating, shock resistant and provides better grip.

Crimping tool A crimping tool is a device used to conjoin two pieces of metal by deforming one or both of them in a way that causes them to hold each other. The result of the tool's work is called a crimp. A good example of crimping is the process of affixing a connector to the end of a cable.

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EXPERIMENT NO:4

TESTING OF ELECTRONIC COMPONENTS

AIM

To familiar with the testing of following Electronic components using multimeter.

 Resistor  Capacitor  Diode  Transistor  UJT  JFET

THEORY

To test resistor with multimeters

To check the value of a resistor, it should be removed from the circuit. The surrounding components can affect the reading and make it lower.

To test capacitor with the Digital Multimeter

1. Make sure the capacitor is discharged.

2. Set the meter on Ohm range (Set it at lease 1000Ohm = 1k). 3. Connect the Meter leads to the Capacitor terminals. 4. Digital meter will show some numbers for a second. Note the reading. 5.And then immediately it will return to the OL (Open Line). Every attempt of Step 2 will show the same result as was in step 4 and Step 5. It‘s mean that Capacitor is in Good Condition.

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6. If there is no Change, then Capacitor is dead.

To test the diode

Digital multimeters can test diodes using one of two methods:

1. Diode Test mode: almost always the best approach. 2. Resistance mode: typically used only if a multimeter is not equipped with a Diode Test mode.

Things to know about the Resistance mode when testing diodes:

 Does not always indicate whether a diode is good or bad.  Should not be taken when a diode is connected in a circuit since it can produce a false reading.  CAN be used to verify a diode is bad in a specific application after a Diode Test indicates a diode is bad.

A diode is best tested by measuring the voltage drop across the diode when it is forward- biased. A forward-biased diode acts as a closed switch, permitting current to flow.

Amultimeter‘s Diode Test mode produces a small voltage between test leads. The multimeter then displays the voltage drop when the test leads are connected across a diode when forward-biased. The Diode Test procedure is conducted as follows:

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1. Make certain a) all power to the circuit is OFF and b) no voltage exists at the diode. Voltage may be present in the circuit due to charged capacitors. If so, the capacitors need to be discharged. Set the multimeter to measure ac or dc voltage as required.

2. Turn the dial (rotary switch) to Diode Test mode ( ). It may share a space on the dial with another function. 3. Connect the test leads to the diode. Record the measurement displayed. 4. Reverse the test leads. Record the measurement displayed.

The diode is REVERSE BIASED in the The diode is FORWARD BIASED in the diagram above and diodes not conduct. diagram above and it conducts

To test the transistor a) Testing an NPN Transistor. Place the three legs of the Transistor first in the E-B-C formation. The multimeter will show the reading if this formation is correct, else it will show over range.

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If the previous method doesn‘t work, place the three legs of the Transistor in the B-C-E formation. If multimeter shows reading then it‘s correct. The reading is nothing but thr HFE of that transistor.

b) Testing PNP Transistor. Place the three legs of the transistor in the same manner as discussed above.

After placing the transistor in the correct formation, multimeter would show the HFEvalue of the transistor.

To test UJT

UJT (Uni- junction transistor) can be easily tested by using a digital multimeter.The three steps for testing the health of a UJT are as follows.

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1.Measuring the resistance between B1 and B2 terminals.

Set your digital multimeter in resistance mode.Connect the positive lead of multimeter to the B1 terminal and negative lead to the B2 terminal.The multimeter will show a high resistance( around 4 to 10K ). Now connect the positive lead to B2 terminal and negative lead to B1 terminal.Again the multimeter will show a high resistance (around 4 to 10K ).Also both the readings will be almost same.

3. Reverse biasing the emitter junction.

Set the digital multimeter in resistance mode. Connect negative lead of the multimeter to the emitter and positive lead to the B1.The multimeter will show a high resistance (around 100‘s of K‘s).Now connect the negative lead once again to the emitter and positive lead to B2.Again the meter will show a high resistance. In both cases the reading will be almost same. This test is almost like reverse biasing a diode.

3. Forward biasing the emitter junction.

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Set the digital multimeter in resistance mode. Connect the positive lead to the emitter and negative lead to B1.The multimeter will show a low resistance (around few 100 ohms).Now connect the positive lead once again to the emitter and negative lead to the B2 terminal. Again the multimeter will show a low resistance reading (around few 100 ohms).In both cases the reading will be almost same. This test is almost like forward biasing a diode.

To test JFET

JFET can be seen as an NPN-type transistor, the gate G corresponds to the base b, the corresponding collector drain D c, S corresponds to the source emitter e. So as long as the measurement as measured transistor PN junction, the reverse resistor. The multimeter dial in the R 100 block, with black pen then one of FET electrodes, then the red pen are the other two poles, when there were two low resistance, the black pen then is the FET gate, the red pen then is the drain or source. Of the JFET, the drain and 105 datasheet and source are interchangeable. For 4-pin JFET, the other pole is shielded pole (using the ground). Testing a JFET with a multimeter might seem to be a relatively easy task, seeing as how it has only one PN junction to test: either measured between gate and source, or between gate and drain.

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Testing continuity through the drain-source channel is another matter, though. Remember from the last section how a stored charge across the capacitance of the gate-channel PN junction could hold the JFET in a pinched-off state without any external voltage being applied across it? This can occur even when you‘re holding the JFET in your hand to test it! Consequently, any meter reading of continuity through that channel will be unpredictable, since you don‘t necessarily know if a charge is being stored by the gate- channel junction. Of course, if you know beforehand which terminals on the device are the gate, source, and drain, you may connect a jumper wire between gate and source to eliminate any stored charge and then proceed to test source-drain continuity with no problem. However, if you don’t know which terminals are which, the unpredictability of the source-drain connection may confuse your determination of terminal identity.

A good strategy to follow when testing a JFET is to insert the pins of the transistor into anti-static foam (the material used to ship and store static-sensitive electronic components) just prior to testing. The conductivity of the foam will make a resistive connection between all terminals of the transistor when it is inserted. This connection will ensure that

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Electronics engineering workshop all residual voltage built up across the gate-channel PN junction will be neutralized, thus ―opening up‖ the channel for an accurate meter test of source-to-drain continuity.

Since the JFET channel is a single, uninterrupted piece of semiconductor material, there is usually no difference between the source and drain terminals. A resistance check from source to drain should yield the same value as a check from drain to source. This resistance should be relatively low (a few hundred ohms at most) when the gate-source PN junction voltage is zero. By applying a reverse-bias voltage between gate and source, pinch-off of the channel should be apparent by an increased resistance reading on the meter.

For n-channel JFET

1. Switch your multimeter to the "Diode Test" position. 2. Hold the positive lead to the JFET's gate terminal. 3. Hold the negative lead to the JFET's source terminal. The multimeter should show a p–n junction forward voltage drop ~ 650-750 mV. 4. Hold the negative lead to the JFET's drain terminal. The multimeter should show a p–n junction forward voltage drop ~ 650-750 mV. 5. Hold the positive lead to the JFET's source terminal. The multimeter should show a low voltage drop - the JFET is ON. 6. Hold the negative lead to the JFET's gate terminal. The multimeter should show a p–n junction reverse voltage drop - overrange. 7. Hold the negative lead to the JFET's gate terminal. Connect the JFET's drain terminal to the JFET's gate terminal. The multimeter should show aoverrange - the JFET is OFF.

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EXPERIMENT NO:5

INTERCONECTION METHODS AND SOLDERING PRACTICE

AIM To familiarize interconnection methods and soldering practice COMPONENTS REQUIRED  Master Appliance Soldering Iron  Knife/blade  Solder  Damp Sponge  Flux to remove oxides THEORY Breadboard

A breadboard is a construction base for prototyping of electronics. Originally it was literally a bread board, a polished piece of wood used for slicing bread. In the 1970s the solder less breadboard became available and nowadays the term "breadboard" is commonly used to refer to these. "Breadboard" is also a synonym for "prototype".Because the solder less breadboard does not require soldering, it is reusable. This makes it easy to use for creating temporary prototypes and experimenting with circuit design. For this reason, solder less breadboards are also extremely popular with students and in technological education. Breadboards are one of the most fundamental pieces when learning how to build circuits. Wire wrap is a process that involves wrapping wires around conductive posts attached to a perf board (a.k.a. a proto board). Another common use of breadboards is testing out new parts, such as Integrated circuits (ICs). When you are trying to figure out how a part works and constantly rewiring things, you don‘t want to have to solder your connections each time.

Soldering Iron

Master Appliance Soldering irons are exceptionally handy and indispensible tools. Professionals and hobbyists alike use soldering irons in various industries and applications. Most commonly, soldering irons are used in the electronic industry. Of course, before you begin a project with your soldering iron, you should know how to use a soldering iron properly and safely. Soldering accomplishes a strong bond between two

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Electronics engineering workshop pieces of metal by joining them together. In this procedure, a material called solder, an alloy mixture of tin and lead, flows over two pre-heated pieces of metal and holds them together. The process is similar to welding but differs because when you weld you are fusing and melting two pieces together to make one. When you solder you are essentially ‗gluing‘ two parts together with molten metal. Most metals with the exception of aluminum, white metal and porous cast iron can be soldered. Below, you will find instructions and illustrations that show you how to use a soldering iron.Solder is used for joining two or more metals at temperatures below their melting points.The popularly used solders are alloys of tin(60%)and lead(40%) that melts at 375ᶿF and solidifies when it cools.

Types of soldering fluxes

Soldering fluxes can be classified as:

(a) Organic Fluxes :Organic fluxes are either rosin or water soluble materials. Rosin used for fluxes are wood gum, and other rosin which are not water soluble. Organic fluxes are mostly used for electrical and electronic circuit making. These are chemically unstable at elevated temperature but non-corrosive at room temperature. (b) Inorganic Fluxes: Inorganic fluxes are consists of inorganic acids; mixture of metal chlorides (zinc and ammonium chlorides). These are used to achieve rapid and active fluxing where formation of oxide films are problems. Fluxes should be removed after soldering either by washing with water or by chemical Soldering and Brazing solvents. The main functions performed by fluxes are : (a) Remove oxide films and tarnish from base part surfaces, (b) Prevent oxidation during heating, and (c) Promote wetting of the faying surfaces. The fluxes should (a) Be molten at soldering temperature (b) Be readily displaced by the molten solder during the process, and (c) Leave a residue that is non-corrosive and non-conductive.

De-soldering

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It is the removal of solder from previously soldered joint .Desolder pump is commonly used device for this purpose .When the solder melts by the action of the soldering iron ,a trigger on the desolder pump should be activated to create vaccum.This vaccum pulls the solder into the tube.

Steps

1. Prepare a work space. Lay down a mat or piece of cardboard that will catch any solder that you drip.

2. Warm your soldering iron. If your soldering iron is electric, you‘ll need to allow it to warm up on its stand. If your soldering iron runs on butane, as Master Appliance soldering irons do, fill it with gas holding the unit firmly with the refill nozzle pointed upwards and press down. Gas will overflow from nozzle when tank is full.

3. Secure the items you are soldering. It helps to have an extra hand while you are soldering. We suggest using a vise or frame to secure your work.

4. Clean your soldering iron. Because soldering irons get so hot, they oxidize and become dirty quickly. They key to reliable connections is clean components so make sure that your soldering tip and parts you are joining are clean. To accomplish this, pass the tip of your soldering iron on a wet sponge until it shines

5. Apply flux. In soldering it often becomes necessary to use materials called fluxes to help remove oxides and keep them absent while you solder. Flux needs to melt at a temperature lower than solder so that it can do its job prior to the soldering action. There are different methods to apply flux. The method you choose will be dependent on the items you are soldering.

6. Tin your soldering iron. If you want to know everything there is to know about how to use a soldering iron, you‘ll need to know how to tin. Tinning is the process of coating a soldering tip with a thin coat of solder. Melt a thin layer of solder on your iron‘s tip. This aids in heat transfer between the tip and the component you are soldering, and also gives the solder a base from which to flow from. This process may need to be repeated as you solder. You will only touch the tip of the soldering iron to the solder when you tin. Do not touch the tip of the iron to the solder while you are actually soldering.

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7. Start soldering. Hold the soldering iron like you would a pen in the hand you write with and the solder in the other.

8. Place the tip of the soldering iron tip. The tip needs to touch both the wire lead and the surface so they achieve the same temperature.

9. Feed solder onto the joint after you have heated the area for two to three seconds. Touch the solder to the side of the connection opposite the soldering iron. Then, let the solder flow only until the connection is covered.

10. Remove the solder first. Then, remove the iron. Make sure the joint remains stationary while it cools.

11. Evaluate. A smooth, shiny and volcano shaped joint is what you are looking for. If this isn‘t what you see, you‘ll need to reheat and feed in more solder.

12. Remove leftover flux with a commercial flux cleaner.

Using a heat sink

There are some components (i.e transistors) that can be damaged by the heat that soldering produces. If you are new to soldering, it‘s good idea to use a heat sink clipped to the lead between the joint and the component‘s body. A cheaper alternative is a standard crocodile clip

Warnings

 DO NOT lay a soldering iron down on any surface. A soldering iron should either be placed on a stand or sealed with a heat resistant cap after every use. Note: Master Appliance's line of soldering irons is butane powered. All of our irons come with heat protective caps.  Soldering should be completed in a well ventilated area.  Lead is present in most solders. Be sure to wash your hands after your project, or better yet wear gloves.  The tip of a soldering iron is very hot. Contact with the tip of a soldering iron would result in a nasty burn.

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 Your soldering iron will perform better if kept clean. A damp sponge can be used to clean residue caused by flux material. A very small skim of flux should be applied to the iron after the cleaning.

Safety precautions in soldering.

 Keep solder iron always on its stand.  All electrically operated instruments/equipment should have proper earthing.  Sometimes emission of (smoke) soldering operation may be poisonous due to a particular type of flux. Operator should have protection from the same.  Flux should be applied gradually while soldering.  While diluting HCl, water should not be added to HCl but HCl should be mixed into the water drop by drop, to avoid accident.  Work place should have enough ventilation and smoking should be strictly prohibited during the operation. Work place should have the facility of first aid.  It should be noted down good quality surface preparation always contributes to good quality joint.

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EXPERIMENT NO:6

PRINTED CIRCUIT BOARD

AIM

To familiarize with printed circuit board (PCB) design and fabricate a single sided PCB with manual etching and drilling.

COMPONENTS REQUIRED

Copper clad sheet, a little paint, drilling machine and ferric chloride solution.

THEORY

Printed circuit board (PCB)

A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board (PWB) or etched wiring board.A PCB populated with electronic connectors and components is called a printed circuit assembly (PCA), printed circuit board assembly or PCB Assembly (PCBA). The vast majority of PCBs are manufactured with "1 ounce copper" on the outer layers. If there are inner layers, they are almost always manufactured with "1/2 ounce copper".

Printed circuit board

The thickness of the copper layer on the PCB affects the behavior of the circuit. PCB copper thickness is usually measured in ounces per square foot, or frequently, just ounces. It can also be given in micrometers, inches or mils."Multi layer" printed circuit

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Electronics engineering workshop boards have trace layers inside the board. One way to make a 4-layer PCB is to use a two- sided copper-clad laminate, etch the circuitry on both sides, then laminate to the top and bottom prepreg and copper foil.

Types of Printed Circuit Boards

1) Single Sided Board

This is the least complex of the Printed Circuit Boards, since there is only a single layer of substrate. All electrical parts and components are fixed on one side and copper traces are on the other side.

2) Double Sided Board

This is the most common type of board, where parts and components are attached to both sides of the substrate. In such cases, double-sided PCBs that have connecting traces on both the sides are used. Double-sided Printed Circuit Boards usually use through-hole construction for assembly of components.

3) Multi Layered Board

Multi layered PCB consists of several layers of substrate separated by insulation. Most common multilayer boards are: 4 layers, 6 layers, 8 layers, and 10 layers. However, the total number of layers that can be manufactured can exceed over 42 layers. These types of boards are used in extremely complex electronic circuits.

Plated-Through Hole (PTH)

For PTH (plated-through holes), additional steps of electro less deposition are done after the holes are drilled, then copper is electroplated to build up the thickness, the boards are screened, and plated with metal. The metal becomes the resist leaving the bare copper to be etched away.

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The picture above is a Plated-Through Hole in an ten layer board. The amount of plating used in the hole depends on the number of layers in the printed circuit board, however only the least amount of metal is used for this process. Holes through a PCB are typically drilled with small-diameter drill bits made of solid coated tungsten carbide.

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EXPERIMENT NO:7

ASSEMBLING OF ELECTRONIC CIRCUIT/SYSTEM ON GENERAL PURPOSE PCB

1. Fixed voltage power supply with transformer, rectifier diode, capacitor and zener/IC regulator AIM: To design and setup fixed voltage power supply with transformer, rectifier, diode, capacitor filter, zener / IC regulator.

COMPONENTS REQUIRED

Diode – 1N4001, BZ 5.1 Capacitor − 470µF, .01µF Function Generator CRO Miscellaneous – Probes, Connecting wires, Bread board, etc.

THEORY Fixed voltage power supply circuit diagram using ic regulator.

5V regulated power supply schematic

This is a small +5V regulated power supply circuit. In that case here we used 7805 Voltage Regulator IC. 7805 is a +5 Volt regulator IC from 78xx chips family. The circuit

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Electronics engineering workshop has internal current limiting and thermal protection capacity. A 9V 2A steps down transformer is used to covert 230V to 9V from mains. Here used a bridge rectifier made by four 1N 4007 diode to convert AC-DC . 470uF 50v as C1 is used for filtering. This circuit is very easy to build. For good performance recommended input voltage 8V-18V. If over 400mA current is needed at output then use a heat sink with the 7805 IC.

12V regulated power supply schematic

Here this circuit diagram is for +12V regulated (fixed voltage) DC power supply. These power supply circuit diagram is ideal for an average current requirement of 1Amp. This circuit is based on IC LM7812. It is a 3-terminal (+ve) voltage regulator IC. It has short circuit protection, thermal overload protection. LM7812 IC is from LM78XX series. The LM78XX series IC is positive voltage regulator IC for different voltage requirements, for example LM7805 IC is made for 5 volt fixed output voltage. There is LM79XX IC series for negative voltage.

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2 - LED blinking circuit using astable multivibrator with transistor BC107.

AIM: To design and setup an LED blinking circuit using astable multivibrator with transistor bc107.

COMPONENTS REQUIRED

Resistors– 470 Ohm Potentiometer− 5 mm , red Capacitor − 47 μF / 16V Transistor − BC107 LED − 5 mm , red THEORY Circuit diagram

This is a simple flashing led circuit with 2 LEDs and 2 NPN transistors.It illustrates the behavior of transistors and capacitors and if you use an oscilloscope it will be very easy to determine what happens in this astablemultivibrator circuit. It‘s state is constantly changing and this change affect the flow of current and voltage and the effect will be visible with the two LEDs.The speed of the led flasher may be adjusted with potentiometer P1. Being an astablemultivibrator, the circuit has no stable state but oscillates continuously between the two states back and forth. The two transistors T1 and T2 turn and lock each other by turn. The smaller the capacitor value is and the smaller the

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Electronics engineering workshop resistance, the appropriate LED goes out faster, for the benefit of other, who then immediately turns on.

The activation time of T2 is t, a = 0.7 x R1 x C1,

The switch-off t off = 0.7 x R2 x C2.

The switch from T1 is t, a = 0.7 x R2 x C2, the off t off = 0.7 x R1 x C1.

It is recommended to always use the equivalent transistors. If one of the transistors is defective, wrong or have a malfunction, so does this to the full functionality of this circuit. One LED lights up and the other is dimmed.

The ―two flashing led‖ circuit is designed for 9 Volts but it works at lower voltages too. In this design we used red leds but by changing the series resistors R1 and R4 you can also use different LED colors

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3- Sine wave generation using ic741 op-amp

AIM:

To design and setup sine wave generation using ic741 opamp in IC base.

COMPONENTS REQUIRED

DC Source, CRO, Bread board, Op-amp, Potentiometer, Capacitors, Resistors, BFW10, 1N4007

THEORY

This is an audio frequency oscillator of high stability and simplicity. The feedback signal in this circuit is connected to the non-inverting input terminal. So that the Op-amp is working as a non inverting amplifier. Therefore, the feedback network need not provide any phase shift. The circuit can be viewed as a Wien bridge with a series RC network in one arm parallel network in adjoining arm. Resistors Ri and Rf are connected in the remaining two arms. The condition of zero phase shift around the circuit is achieved by balancing the bridge. The frequency of oscillation is the resonant frequency of the 1 balanced bridge and is given by the expression f0 = . From the analysis of the circuit, 2휋 RC it can be seen that the feedback factor β=1/3 at the frequency of oscillation. Therefore, for the sustained oscillation the amplifier must have a gain of 3. An FET circuit in association with the wein bridge oscillator, helps the stabilization of the amplitude stabilization. The N-channel JFET acts as a voltage controlled resistor. The dc voltage at the gate of FET becomes more negative when amplitude of oscillation increases. Then gate of FET gets reverse biased and effective resistance from drain to source increases. This causes to 푅 0 decrease the gain according to the relation A = 1+ and amplitude is brought back to a 푅푖 stable level. When the amplitude of oscillation decreases. Opposite effect occurs.

DESIGN:-

Wein Bridge Oscillator:-

The required frequency of oscillation f0 = 1 KHz

1 Given f0 = 2휋RC Let C = 0.1µF. Then R = 1.6 k (Use 1.5 K std)

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푅푓 Gain 1+ = 3 푅푖 Let Ri = 1 K, Then Rf = 2.2 K ( Use 4.7 K Pot Std)

Wein Bridge Oscillator with Amplitude Stabilization:-

The required frequency of oscillation f0 = 1 KHz

1 Given f0 = 2휋RC Let C = 0.1µF. Then R = 1.6 k (Use 1.5 K std)

푅푓 Gain 1+ = 3 푅푖 Let Ri = 1 K

CIRCUIT DIAGRAM

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4. Square wave generator using 555 Timer

Square wave generator using 555 Timer is very simple, easy to design, very stable and low cost. It can be used for timing from microseconds to hours. Due to these reasons 555 has a large number of applications and it is a popular IC among electronics hobbyists.

Above figure shows the circuit diagram of a 555 Timer wired in Astable Mode. 8th pin and 1st pin of the IC are used to give power, Vcc and GND respectively. The 4th pin is RESET pin which is active low and is connected to Vcc to avoid accidental resets. 5th pin is the Control Voltage pin which is not used. So to avoid high frequency noises it is connected to a capacitor C2 whose other end is connected to ground. Usually C2 = 0.01μF.

The Trigger (pin 2) and Threshold (pin 6) inputs are connected to the capacitor (C1) which determines the output of the timer. Discharge pin (pin 7) is connected to the resistor Rb such that the capacitor can discharge through Rb. Diode D connected in parallel to Rb is only used when an output of duty cycle less than or equal to 50% is required.

Working

Since the Control Voltage (pin 5) is not used the comparator reference voltages will be 2/3 Vcc and 1/3 Vcc respectively. So the output of the 555 will set (goes high) when the capacitor voltage goes below 1/3 Vcc and output will reset (goes low) when the capacitor voltage goes above 2/3 Vcc.

When the circuit is switched ON, the capacitor (C) voltage will be less than 1/3 Vcc. So the output of the lower comparator will be HIGH and of the higher comparator will be LOW. This SETs the output of the SR Flip-flop. Thus the discharging transistor will be OFF and the capacitor C starts charging from Vcc through resistor Ra &Rb. When the capacitor voltage will become greater than 1/3 Vcc( less than 2/3 Vcc ), the output of MCET Pathanamthitta Page 116

Electronics engineering workshop both comparators will be LOW and the output of SR Flip-flop will be same as the previous condition. Thus the capacitor continuous to charge.

When the capacitor voltage will becomes slightly greater than 2/3 Vcc the output of the higher comparator will be HIGH and of lower comparator will be LOW. This resets the SR Flip-flop. Thus the discharging transistor turns ON and the capacitor starts discharging through resistor Rb. Soon the capacitor voltage will be less than 2/3 Vcc and output of both comparators will be LOW. So the output of the SR Flip-flop will be the previous state. So the discharging of capacitor continuous. When the capacitor voltage will become less than 1/3 Vcc, the output SETs since the output of lower comparator is HIGH and of higher comparator is LOW and the capacitor starts charging again. This process continuous and a rectangular wave will be obtained at the output.

Design

Capacitor Charges through Ra and Rb.

Therefore,

TON = 0.693(Ra + Rb)C

Capacitor Discharges through Rb

TOFF = 0.693RbC

Duty Cycle = TON/(TON + TOFF)

Where TON and TOFF are the time period of HIGH and LOW of the output of 555.

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EXPERIMENT NO:8

FAMILIARIZATION OF ELECTRONIC SYSTEMS

1. Setting up of a PA System with different microphones, loud speakers and mixer

AIM

To setup a basic PA system.

THEORY

A Public Address or PA system is composed of 3 main components - a sound source, an amplifier and a loudspeaker. The sound source can be a number of things. It is normally a microphone or a playback device such as a cassette deck or a CD player. The sound source produces an electrical signal that represents the sound. The amplifier is used to increase the level of the electrical signal from the sound source so that it can be heard at sufficient volume from the loudspeaker. Finally, the loudspeaker is the device which converts the electrical impulses from the amplifier into vibrations in the air which our ear interprets as sounds. Additionally, you will normally be dealing with multiple sound sources. In order to control these properly a Mixer is used to add the sounds together so that a single signal can be sent to the Amplifier. Mixers also have other roles. Some sound sources have very weak signals (microphones especially) which are not suitable for direct connection to an amplifier. The mixer provides what is known as a Pre-amplifier that will boost the input signal up to a suitable level. This is also referred to as Input Gain  Sound sources Sound sources vary widely. They can be microphones for capturing sounds from voices or instruments. They can be from a recorded media such as CD or Minidisc or Cassette. Or, in broadcast situations, they may be from a radio transmission or the telephone. Whatever the source is we need to understand its properties so that we can connect it properly to our PA system. Microphones produce a very weak signal. They are essentially the reverse of a loudspeaker where the vibrations in the air cause movements in a small diaphram in the microphone capsule. The resulting electrical signal is very weak and needs to be boosted before it can be sent to an amplifier. This is the job of a Pre-amplifier. These devices can be found in most mixers as mentioned above but they can also exist as separate units in some cases.  Amplifiers As we said earlier, amplifiers take a line-level signal and boost it to the levels required to drive a loudspeaker. We refer to all these amplifiers as Power Amplifiers as they handle the high powers required to drive loudspeakers.

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 Power The main parameter you will pay attention to when selecting an amplifier is the Output Power. This is expressed in Watts - e.g. 650 Watts. Care must be taken here as the power delivered by an amplifier depends on the load being driven by the amplifier - in our case, the loudspeaker.

 Load The load in this case is the loudspeaker. Each loudspeaker has an electrical characteristic called the Impedance and is expressed in Ohms (W). It is a measure of the resistance offered by the loudspeaker.  Loudspeakers

The loudspeaker is the final link in the chain. In essence it is a very simple device but is takes careful design and construction to produce a unit that delivers clear, precise sound. A loudspeaker is essentially a box or cabinet containing one or more Drivers that produce the actual sound.  Impedance We mentioned Impedance when we talked about amplifiers. This is a measure of the Load that the speaker represents to the amplifier. It is measured in Ohms (W). Most speakers have an Impedance of either 4W, 8W or 16W. This figure must be taken into account when choosing the correct amplifier to use. But what happens when you want to connect two or more loudspeakers to the same amplifier channel? Does the impedance change? Well, yes it does, but not as you may expect. When speakers are connected together they are connected in parallel. When this happens the following maths applies: 1 1 1 = + + … … 푇표푡푎푙 퐼푚푝 퐼푚푝 퐴 퐼푚푝 퐵 To deal with more than two loads you just keep on adding terms to the right. So two 8W speakers would give a total of 4W and three 8W loads would give you a total load of 2.67W. Be careful not to make the load too small. Most amplifiers have a minimum load that they can drive, 2W being the common minimum. Always check the specifications of the equipment.  Mixer If we want to combine the audio signals from more than one source the obvious thought would be to connect all the wires together. In practice this doesn't really work due to various electrical properties such as impedance, phase cancelation and noise. What we require is a device that combines the signals properly and gives us control over the balance between each input. This is the job of the Mixer. In its simplest form a mixer has several inputs and a single output where the combined signal comes out. To give us a little more control, individual level (volume) controls are fitted to the inputs and a master level control to the output. This then allows us to not only

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control the overall output level from the unit but also the balance between the individual inputs. Most mixers have more functionality than this and we need these extra functions when setting up a PA system. We will now describe the functions of a typical Mixing Desk (also referred to by some as a Console). The desk can be split into 3 main areas. The Channel Strip - This contains the controls for each input. Multiple channel strips are to be found on a mixer, normally in multiples of 4 or 8 - e.g. 4,8,12,16,24,32. This simply corresponds to the number of inputs that the desk can support. The Master Section - This containes the Output level controls and other controls that affect the overall output of the mixer. The Connection Panel - This contains the various connectors for attaching the inputs and outputs and other auxiliary equipment. We will now take a look at each of these in detail. It should be noted that no two mixers are the same and the one you are using may have more or less features than are described here. All the basics operating procedures, however, are the same.  Equaliser The EQ or Equaliser section allows control over the tone of the audio signal. Simple mixers may just have two controls - Bass and Treble. Slightly better ones have a Mid- band control too. The best ones have Parametric control that allow you to select the frequency on which the control is acting. The one shown in the diagram has 2 parametric bands allowing for good control over the signal. EQ is used not only to control how something 'sounds' but can also be used to help correct problems such as feedback and to create particular effects. If you use more than one brand of mixers you may hear differences between the EQ sections from different manufacturers. This is one of the reasons that some engineers favour a particular brand of mixing desk.  Cables & Connections Cables, although among the cheapest items in a PA, are very important. These carry the audio signals between components and should therefore be chosen carefully in order to minimise losses and interference which could degrade the resulting sound.

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2. Assembling of desktop computer

AIM

To assemble a desktop computer.

THEORY

Computer Parts

A computer is made up of a case, also called a chassis, which houses several internal components, and the external components, including peripherals. Inside the case go the following internal parts:

• Power Supply/PSU power supply unit: It converts the outlet power, which is alternating current (AC), to direct current (DC), which is what the internal components require, as well as providing appropriate voltages and currents for the various internal components.

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• Motherboard/mainboard: As the name indicates, this is the electronic centerpiece of the computer, everything else connects to the motherboard.

• Processor/CPU central processing unit: It is the ―brain‖ of the computer, most actual computation takes place here.

• RAM random access memory: It is the ―short-term memory‖ of a computer, used by the CPU to store program instructions and data upon which it is currently operating. Data in RAM is lost when the computer is powered off, thus necessitating a hard drive.

• Hard Drive/Hard Disk: It is the ―long-term memory‖ of the computer, used for persistent storage i.e. the things stored on it remain even when the computer is powered down. The operating system, and all your programs and data are stored here.

• Optical Drive device for reading/writing optical disks: May read CDs, DVDs, or other optical media, depending on the type. It is essential for installing many operating systems and programs. It may be able to write some of these discs, as well. Some people like to have two such drives for copying disks.

• Video Card/Graphics Card/GPU: It does processing relating to video output. Some motherboards have an ―onboard‖ GPU built in so you don‘t need (but may add) a separate video card. Otherwise, you will need a video card. These plug into a slot on the motherboard and provide a place to connect a monitor to your computer.

On top of the internal components listed above, you will also need these external components:

• Keyboard for typing on. Many motherboards won‘t even boot without a keyboard attached.

• Mouse for pointing and clicking. Unless you chose a text-based operating system, you will likely want one of these.

• Monitor this is where the pretty pictures go. They come in many forms, the most common being CRT and LCD.

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COMPUTER ASSEMBLY - PROCEDURE

Motherboard Find the motherboard standoffs that should have come with the case. They are screws, usually brass, with large hexagonal heads that are tapped so you can fasten screws into the top. Remove the I/O Shield from the back of the case where the ports on the back of the motherboard will fit, and put in the I/O Shield that came with your motherboard. There may be small metal tabs on the inside of this face plate, if so you may have to adjust them to accommodate the ports on the back of the motherboard. Some case styles make it difficult to install the motherboard or the CPU with the power supply installed. If the power supply is in your way, take it out and set it aside (we‘ll put it back in later).

Now locate the screw holes on your motherboard and find the corresponding holes on the motherboard plate (or tray) in the case. Put a standoff in each of these holes on the tray and position the motherboard so that you can see the holes in the top of the standoffs through the screw holes in the motherboard. Now is the time to make sure the ports on the motherboard are mating with the back plate you just installed, and make any necessary adjustments. The small metal tabs are intended to make contact with the metal parts of the connections on the back of the motherboard and ground them, but you may have to bend these tabs a bit to get the ports all properly mounted. Now fasten a screw through each of the motherboard screw holes into the standoffs underneath. These screws should be snug but not tight, there is no reason to torque down on them, hand tight is fine, otherwise you can damage the motherboard.

CPU Installing the CPU, and the CPUs heatsink and fan, are by far the most difficult steps youll have to complete during your build. Some operations, especially installing the heatsink/fan combination, can require pretty firm pressure, so don‘t be afraid to push a little harder if you are sure everything is set up correctly. The details of the installation process differ in slight but important ways for each manufacturers processors, and even within a manufacturers product line. Therefore, for these details, you should rely on the instructions that are provided with the CPU.

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The two things that go wrong the most often and most expensively (minimum of a killed CPU, sometimes more) in building one‘s own computer are both related to the CPU and its cooler: 1. Switching the computer on ―just to see if it works‖ before adding any CPU cooling unit. Without cooling, CPUs heat up at extreme rates (a CPU heats up anywhere between ten times and a thousand times as fast as a cooking area on your stove!) By the time you see the first display on the screen, your CPU will already be severely overheating and might be damaged beyond repair. 2. Mounting the CPU cooler improperly. Read the instructions that came with your CPU and cooler very carefully and ensure you are using all components in the correct order and correct place.Tighten the cooler using only the specified holding devices—if you did everything right, they will fit. If they don‘t fit, check your setup—most likely something is wrong. After mounting the cooler, connect any power cables for the fan that is attached onto the cooler.

RAM Next, you will need to install your RAM (random access memory). To install the RAM modules, first push on the levers (white plastic in the picture) on either side of the DIMM socket, so that they move to the sides. Do not force them, they should move fairly easily. Put the RAM module in the socket. Line up the notch in the center of the module with the small bump in the center of the RAM socket, making sure to insert it the right way. Push down on the module until both levers move up into the notches on the sides of the module. There should be a small ―snap‖ when the module is fully seated. Although this does require a fair bit of force, don‘t over do it or you may break the RAM module. Take a good look at your seated RAM, if one side seems to be higher than the other, odds are it‘s improperly seated—take it out and try again. As you handle the RAM, try not to touch the copper stripes you can see along the bottom edge, as doing so is the best way to damage the part. Start adding RAM at the slot labeled ―Bank 0‖ or ―DIMM 1‖. If you don‘t have a stick in ―Bank 0‖ or ―DIMM 1‖ the system will think there is no RAM and won‘t boot. On newer motherboards with 4 slots, you‘ll see alternating colours. For example, slot 1 is blue, slot 2 is black, slot 3 is blue, slot 4 is black. If you were to put 1 gigabyte of RAM in your PC, it‘s best to use dual channel 512MBx2 sticks. Put the first 512MB stick

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Electronics engineering workshop in slot 1, and put the 2nd stick in slot 3 (the two slots that are blue)—leaving slot 2 empty. This will give you better performance, vs. putting 1GB in slot 1, or two 512MB sticks in slot 1 and 2.

Power Supply Installing your power supply is pretty straightforward, if it came with your case it was preinstalled and if you took it out earlier to get the motherboard in, now is the time to put it back. Otherwise a few moments of screwdriver work will get the job done. Generally there will be a bracket on the top of the case where the power supply is mounted and a few screws used to fix it in place. Some cases place the PS differently, see the documentation that came with yours. If your power supply has a switch to select 115v or 220v make sure it is set properly, this is important. Many newer power supplies can automatically select and dont have such a switch. Once you get the power supply installed you should plug the main power, a 20 or 24 pin plug, into the motherboard. There may also be an additional four or eight pin power lead on the motherboard that needs to be plugged in, this is usually located near the processor socket. Make sure you check the motherboard documentation carefully for the location of the power sockets.

Installing drives

Next install the hard drive and optical drives. How a drive is physically installed will depend on the case. When using an IDE cable, plug the two connectors that are closer together into the 2 drives, and the third to the controller or motherboard. The connector furthest from the board should be attached to the drive set as Master. Make sure the drive that you will install your OS on is the primary master. This is the master drive on the Primary IDE bus which is usually the IDE 40 pin port on the motherboard labelled Primary or IDE 1.

Other connections

In order to turn the computer on, you will need to connect the power button and while you‘re at it, you might as well do the reset buttons and front panel lights as well. There will be a set of pins, usually near the front of the motherboard to which you will attach the cables that should have been supplied with the motherboard.

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These will plug into the front of the case. The plugs in the front of the case will be labelled. The pins on the motherboard may be labelled as well. The documentation that came with your case and motherboard should tell where these connectors are. The front panel LEDs are polarized: usually the positive wire is white. In addition, you can connect any case-specific ports if they are supported by the motherboard.

Power up

Before power turns ON, you want to have the computer open, so that you can see all of the fans, and youll need to connect a monitor and a keyboard and a mouse. Monitors will either have a VGA or a newer DVI plug. Most monitors use VGA connectors, and so most graphics cards have VGA output. There are two standard connectors for mice and keyboards; PS/2 connectors and the more modern USB connectors. Plug the mouse and keyboard in the appropriate slot. Turn on the monitor, then press the power button, and observe the inside of the open machine. (Do not touch any part of the inside of the machine while it is powered up). The first thing to look for is that the CPU cooler fan spins up, if it does not, cut the power immediately. This fan should start up right away; something is wrong if it doesn‘t and your CPU is in danger of overheating so stop now and troubleshoot.

If the CPU fan spins up, check that all the other fans that should be spinning case fans and fans on the power supply and video card (if installed) are also spinning. Some of these fans may not spin up until a temperature threshold is passed, check your documentation if anything is not spinning. If the fans spin, you can turn your attention to the monitor, what you are hoping to see is the motherboards splash screen, usually featuring the manufacturer‘s logo. If you see this, take a moment to bask in the glow, you have built a computer!

Note: If it does not occur, if smoke appears, or if the computer doesn‘t do anything, unplug the power cord immediately and check the steps above to make sure you haven‘t missed anything. Give special attention to the cables and power connections. If the computer does appear to come on, but, you hear beeps, listen carefully to the beeps, turn the computer off, and refer to your motherboard‘s manual for the meaning of the beeps. Some boards have an optional diagnostic device, usually a collection of LEDs, which when properly plugged in will inform you of the nature of the problem. Instructions for

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Electronics engineering workshop installing this as well as the meaning of its display should be in the manual for the motherboard. If the computer turns on but the only thing that comes on is your power supply, turn it off. This probably means something is shorted, and leaving it on could damage the parts.

Installing softwares

Now that you have got a functioning computer, you will need to install some software if you are going to do anything with it. An operating system must come first, then hardware drivers (so that the operating system can address your hardware) followed by security software and utilities. Choosing between Microsoft Windows, GNU/Linux, or one of the other operating systems is largely dependent on what software you need to run. Microsoft Windows is better in terms of software availability, hardware compatibility and support, but GNU/Linux wins in terms of stability, ability to run on older equipment, and cost.

For installing operating system, push the button on the front of the PC, put the CD-ROM in your optical drive, and follow the on-screen instructions.

Steps for Assembly: 1. Prepare the Mainboard (motherboard). If you want to assemble the well-liked device, you should use Intel i3,i5,i7 Mainboard.

2. Mount the CPU in the socket of the Mainboard. You must choose the correct CPU for your motherboard, and install it according to it's instructions. Be careful not to install the CPU in wrong. Not only would your computer not work, it could short-circuit and damage your motherboard.

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3. Connect the CPU cooler to the Mainboard.

4. Attach the RAM(memory) modules in the corresponding slots. The motherboard should have rows of slots that have 2 or 3 sections that are different lengths. Make sure the pins on the RAM cards line up with the pins on the motherboard connector. Don't get the RAM slots mixed up with PCI slots. The PCI slots are usually wider.

5. Open the case and mount the power supply which is M-ATX type. Make sure to connect all the connections to the drives and the motherboard.

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6. Attach the Mainboard back plate to the case and check the Mainboard mounting positions. The motherboard's instructions should tell the position of the motherboard.

7. Suitably position the Mainboard in the case.

8. Mount the Hard disk and connect it to the power supply and the motherboard. There should be separate connections for the power supply and the motherboard. In SATA Hard disk case, should remove the jumper.

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9. Connect the 20 or 24 pin ATX connector and the 4-pin power supply control connector to the motherboard.

10. Mount the DVD-ROM drive. After connecting the ATA cable to the device, hook it up to the power supply.

11. Finally, select a compatible operating system, and follow the instructions to install.

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3. Familiarization of components used in robotics

AIM To familiarize with various Components used in robotics such as; Sensors Motors Batteries

THEORY

A robot is ―intelligent‖, a man made device that can move by itself, whose motion can be modeled, planned, sensed and controlled and who‘s motion and behavior can be influenced by programming. A robot is a general purpose, programmable manipulator. In practice it is usually an electro- mechanical system which by its movements and appearance conveys that it has intent of its own. a). Sensors Used in Robotics The use of sensors in robots has taken them into the next level of creativity. Most importantly, the sensors have increased the performance of robots to a large extent. It also allows the robots to perform several functions like a human being. The robots are even made intelligent with the help of Visual Sensors (generally called as machine vision or computer vision), which helps them to respond according to the situation.

Different types of sensors

There are plenty of sensors used in the robots, and some of the important types are listed below.

Light sensors

A Light sensor is used to detect light and create a voltage difference. The two main light sensors generally used in robots are Photo resistor and Photovoltaic cells. Other kinds of light sensors like Phototubes, Phototransistors, CCD‘s etc. are rarely used.

Photo resistor is a type of resistor whose resistance varies with change in light intensity; more light leads to less resistance and less light leads to more resistance. These inexpensive sensors can be easily implemented in most light dependant robots.

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Fig: Light Sensors

Sound Sensor

As the name suggests, this sensor (generally a microphone) detects sound and returns a voltage proportional to the sound level. A simple robot can be designed to navigate based on the sound it receives. Imagine a robot which turns right for one clap and turns left for two claps. Complex robots can use the same microphone for speech and voice recognition.

Fig: Sound Sensor (Mic)

Implementing sound sensors is not as easy as light sensors because Sound sensors generate a very small voltage difference which should be amplified to generate measurable voltage change.

Temperature Sensor

Tiny temperature sensor ICs provide voltage difference for a change in temperature. Few generally used temperature sensor IC‘s are LM34, LM35, TMP35, TMP36, and TMP37.

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Fig: Temperature Sensor LM35

Contact sensors

Contact sensors are those which require physical contact against other objects to trigger. A push button switch, limit switch or tactile bumper switch are all examples of contact sensors. These sensors are mostly used for obstacle avoidance robots. When these switches hit an obstacle, it triggers the robot to do a task, which can be reversing, turning, switching on a LED, Stopping etc. There are also capacitive contact sensors which react only to human touch.

Fig: Contact sensor (Push Button Switch

Proximity Sensors

This is a type of sensor which can detect the presence of a nearby object within a given distance, without any physical contact. The working principle of a Proximity sensor is simple. A transmitter transmits an electromagnetic radiation or creates an electrostatic field and a receiver receives and analyzes the return signal for interruptions. There are

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Electronics engineering workshop different types of Proximity sensors and we will discuss only a few of them which are generally used in robots.

 Infrared (IR) Transceivers: An IR LED transmits a beam of IR light and if it finds an obstacle, the light is simply reflected back which is captured by an IR receiver. Few IR transceivers can also be used for distance measurement.  Ultrasonic Sensor: These sensors generate high frequency sound waves; the received echo suggests an object interruption. Ultrasonic Sensors can also be used for distance measurement.  Photo resistor: Photo resistor is a light sensor; but, it can still be used as a proximity sensor. When an object comes in close proximity to the sensor, the amount of light changes which in turn changes the resistance of the Photo resistor. This change can be detected and processed.

Fig: IR Transceivers

Positioning sensors

Positioning sensors are used to approximate the position of a robot, some for indoor positioning and few others for outdoor positioning.

 GPS (Global Positioning System): The most commonly used positioning sensor is a GPS. Satellites orbiting our earth transmit signals and a receiver on a robot acquires these signals and processes it. The processed information can be used to determine the approximate position and velocity of a robot. These GPS systems are extremely helpful for outdoor robots, but fail indoors. They are also bit expensive at the moment and if their prices fall, very soon you would see most robots with a GPS module attached.

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Electronics engineering workshop b). Motors Used in Robotics

Electric motors are used to ―actuate‖ something in your robot: its wheels, legs, tracks, arms, fingers, sensor turrets, or weapon systems.

DC Motor

In a continuous DC motor, application of power causes the shaft to rotate continually. The shaft stops only when the power is removed, of if the motor is stalled because it can no longer drive the load attached to it. Typical DC motors may operate on as few as 1.5 Volts or up to 100 Volts or more. Roboticists often use motors that operate on 6, 12, or 24 volts because most robots are battery powered, and batteries are typically available with these values.

Fig: DC Motor

Stepper Motor

Stepper motors are DC motors that move in discrete steps. They have multiple coils that are organized in groups called "phases". By energizing each phase in sequence, the motor will rotate, one step at a time. Stepper motors have several electromagnetic coils that must be powered sequentially to make the motor turn, or step, from one position, to the next. By reversing the order that the coils are powered, a stepper motor can be made to reverse direction. The rate at which the coils are respectively energized determines the velocity of the motor up to a physical limit. Typical stepper motors have two or four coils.

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Electronics engineering workshop

Fig: Stepper Motor

Servo Motor

Standard servo motors have three wires, which are for power ( 4 – 6 V), ground and control. The size and shape of the servo motors are dependent on the application. RC servo motor are the common type of servo motors used in robotics and hobby applications due to their affordability, reliability, and simplicity of control by microprocessors.RC servo motors are low power servos that can be powered from small batteries and other DC supplies in the range of 100 mA to 2 A. There are also high power servo motor types which are powered from AC supplies and used in industrial applications. Although the microcontroller (the robot‘s brain) decides the speed and direction of the motors, it cannot drive them directly because of its very limited power (current and voltage) output. The motor controller, on the other hand, can provide the current at the required voltage but cannot decide how fast the motor should turn. Thus, the microcontroller and the motor controller have to work together in order to make the motors move appropriately.

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Fig: Servo Motor

Small motors are engineered for applications where compactness is valued over torque. While there are small high-torque motors, these tend to be expensive because they use rare earth magnets, high efficiency bearings, and other features that add to their cost.

Large motors may produce more torque, but also require higher currents. High current motors require larger capacity batteries, and bigger control circuits that won‘t overheat and burn out under the load. Therefore, match the size of the motor with the rest of the robot. Don‘t overload a small robot with a large motor when big size isn‘t important.

When decided on the size of the motor, compare available torque after any gear reduction. Gear reduction always increases torque. The increase in torque is proportional to the amount of gear reduction: if the reduction is 3:1, the torque is increased by about three times. c). Batteries Used in Robotics

Batteries are the main component of a robotic system. Batteries can be classified into rechargeable or non-rechargeable. Non-rechargeable batteries deliver more power based on their size, and are suitable for certain applications.

Alkaline batteries are inexpensive, and lithium batteries, on the other hand exhibit a longer shelf life and better performance.Common rechargeable batteries such as nickel-cadmium (NiCd) and lead acid batteries deliver a smaller voltage than alkaline batteries. They are found in battery packs along with specialized power connectors. Gelled lead acid batteries

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Electronics engineering workshop are widely used and capable of providing power of up to 40Wh/kg.Lithium-ion, nickel metal hydride and silver zinc batteries are some of the other rechargeable battery technologies that offer significantly increased energy density.

Photovoltaic Cells

Photovoltaic or solar cells can be used to charge the batteries of the robotic systems. They are used in conjunction with a capacitor and can be charged up to a set voltage level and then be discharged via the movements of motor. These cells are chiefly used in BEAM robots.

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APPENDIX – A STANDARD VALUES OF COMPONENTS Typical Standard value Resistors

10% TOELRANCE RESISTORS

Ω Ω Ω KΩ KΩ KΩ MΩ MΩ

− 10 100 1 10 100 1 10

− 12 120 1.2 12 120 1.2 12

− 15 150 1.5 15 150 1.5 15

− 18 180 1.8 18 180 1.8 18

− 22 220 2.2 22 220 2.2 22

2.7 27 270 2.7 27 270 2.7 −

3.3 33 330 3.3 33 330 3.3 −

3.9 39 390 3.9 39 390 3.9 −

4.7 47 470 4.7 47 470 4.7 −

5.6 56 560 5.6 56 560 5.6 −

6.8 68 680 6.8 68 680 6.8 −

8.2 82 820 8.2 82 820 8.2 −

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5% TOLERANCE RESISTORS Ω Ω Ω KΩ KΩ KΩ MΩ MΩ − 10 100 1 10 100 1 10 − 11 110 1.1 11 110 1.1 11 − 12 120 1.2 12 120 1.2 12 − 13 130 1.3 13 130 1.3 13 − 15 150 1.5 15 150 1.5 15 − 16 160 1.6 16 160 1.6 16 − 18 180 1.8 18 180 1.8 18 − 20 200 2 20 200 2 20 − 22 220 2.2 22 220 2.2 22 − 24 240 2.4 24 240 2.4 − 2.7 27 270 2.7 27 270 2.7 − 3 30 300 3 30 300 3 − 3.3 33 330 3.3 33 330 3.3 − 3.6 36 360 3.6 36 360 3.6 − 3.9 39 390 3.9 39 390 3.9 − 4.3 43 430 4.3 43 430 4.3 − 4.7 47 470 4.7 47 470 4.7 − 5.1 51 510 5.1 51 510 5.1 − 5.6 56 560 5.6 56 560 5.6 − 6.2 62 620 6.2 62 620 6.2 − 6.8 68 680 6.8 68 680 6.8 − 7.5 75 750 7.5 75 750 7.5 − 8.2 82 82 8.2 82 82 8.2 − 9.1 91 910 9.1 91 910 9.1 −

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Typical Standard value Capacitors

STANDARD VALUE CAPACITORS

Code (pF) (nF) (μF) Code (pF) (nF) (μF)

100 10 0.01 0.00001 472 4700 4.7 0.0047 0.01 150 15 0.000015 502 5000 5.0 0.005 5 0.02 220 22 0.000022 562 5600 5.6 0.0056 2 0.03 330 33 0.000033 682 6800 6.8 0.0068 3 0.04 470 47 0.000047 103 10000 10 0.01 7 101 100 0.1 0.0001 153 15000 15 0.015 121 120 0.12 0.00012 223 22000 22 0.022 131 130 0.13 0.00013 333 33000 33 0.033 151 150 0.15 0.00015 473 47000 47 0.047 181 180 0.18 0.00018 683 68000 68 0.068 10000 221 220 0.22 0.00022 104 100 0.1 0 15000 331 330 0.33 0.00033 154 150 0.15 0 20000 471 470 0.47 0.00047 254 200 0.2 0 22000 561 560 0.56 0.00056 224 220 0.22 0 33000 681 680 0.68 0.00068 334 330 0.33 0 47000 751 750 0.75 0.00075 474 470 0.47 0 68000 821 820 0.82 0.00082 684 680 0.68 0 10000 102 1000 1.0 0.001 105 1000 1.0 00 15000 152 1500 1.5 0.0015 155 1500 1.5 00 20000 202 2000 2.0 0.002 205 2000 2.0 00 22000 222 2200 2.2 0.0022 225 2200 2.2 00 33000 332 3300 3.3 0.0033 335 3300 3.3 00

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