Common electronic components

Electronics Klas Granqvist Akun Tehdas / Oy Aku’s Factory Ltd • When comparing the topics ”power” and ”electronics” the latter one deals with significantly smaller and ”weaker” systems • Common voltages in electronic circuits are in the range of 1,5 -18 V and the currents are measured in a couple of hundred mA:s • A very cheap and intuitive hobby • Basic components are really cheap when a ±20% tolerance is acceptable • Especially when trying out audio circuitry the results may often be interesting an unexpected Components • Small items and devices that the circuits consist of • The most common components are typically very small in size and really affordable • The price range is around € 0,10 - € 5,00 for the ones most used • A certain tolerance has to be accepted in this price range • Components may different intended uses and various functions depending on the way they are connected • The voltages and currents among the most typical components are very small • The circuits are battery driven and do not work with very much power (usually 9 V / 3 A max) • Passive components work as themselves, active components need an external voltage How much is the fuzz? How much is the fuzz? • 1 pc IC 741 741: 0,72 € • 2 pcs 100 kΩ / 0,25W: 0,20 € (total) • 1 pc resistor 1000 Ω / 0,25 W: 0,20 € • 1 pc resistor 1 MΩ / 0,25 W: 0,20 € • 1 pc electrolyte 100 µF / 16 V: 0,15 € • 2 pcs ceramic capacitor 0,47 µF: 0,30 € (total) • 2 pcs 1N4148: 0,10 € (total) • 2 pcs jack (0,50 €), battery clip € / 100 m), circuit board (3,00 €), plastic casing (4,00 €): The fuzz? How much is the fuzz?

€ 11,16 Colour coding • Due to their small size the components seldom contain all the information in written text • Many features of the components are expressed by using colour coding • Each colour has its own value • Also the order of the colours plays a role Basic colour coding

Colour Number

Black 0 Brown 1 ”Black bears Red 2 raid our young Orange 3 Yellow 4 great blokes Green 5 violently Blue 6 Purple (violet) 7 grabbing Gray 8 whales” White 9 Resistor • A small passive component that has a key feature of resisting the flow of an • Consists of two pieces of conductor that are joint by a less conducting material • Carbon composire, carbon foil, metal foil etc. • Not an isolating material Resistor • The key operations are usually restricting the current or adjusting the voltage top a desired level • For instance adjusting the current to light an LED (ca. 20 mA) • Set the voltage for an active component (, IC…) • When the voltage or the current drops, a part of the electricity is dissipated as heat Resistor • The resistor value in ohms is indicated by colour rings (commonly four detonating rings and one tolerance ring) • The leftmost ring indicates the value of 102:s, the ”hundreds” • The next ring indicates the value of 101:s, the ”tens” • The third ring indicates the value of 100:s, the ”ones” • The fourth ring indicates a multipliers as 10x, which can also be thought of as ”how many zeros is added to the end of the value” • The fifth ring indicates the tolerance of the nominal value • The tolerance ring should be clearly separated from the value rings • Usually a different colour than the value rings (silver → 10%, gold → 5%) • In some occasions the actual value can be indicated with only three rings (then the 102:s os omitted) Resistor, example • Value ring combination: yellow-purple-black-black • Yellow → 4 → hundreds → 400 • Purple → 7 → tens → 70 • Black → 0 → ones → 0 • The first three rings: 400 + 70 + 0 → 470 • Black → 100 = 1 → multiplied by one, or ”no zeros added to the and” • The nominal resistance of the resistor is 470 Ω • If the tolerance ring is silver coloured (± 10%) the allow actual value ranges between 423-517 Ω Resistor, illlustration

5. ring = “tolerance”

4. ring= “zeros added” 1. ring = “hundreds” 3. ring = “ones”

2. ring = “tens” Colour coding of resistors

Colour 1. ring 2. ring 3. ring Multiplier Tolerance

Black 0 0 0 100 = 1 Ω -

Brown 1 1 1 101 = 10 Ω ± 1 %

Red 2 2 2 102 = 100 Ω ± 2 %

Orange 3 3 3 103 = 1 kΩ -

Yellow 4 4 4 104 = 10 kΩ -

Green 5 5 5 105 = 100 kΩ ± 0,5 %

Blue 6 6 6 106 = 1 MΩ ± 0,25 %

Purple 7 7 7 107 = 10 MΩ ± 0,1 %

Gray 8 8 8 - ± 0,05 %

White 9 9 9 - -

Gold - - - 10-1 = 0,1 Ω ± 5 %

Silver - - - 10-2 = 0,01 Ω ± 10 % Resistor, example • Four-ring resistors still exist as well • The ring indicating the ”hundreds” is missing • 1. ring → 101 → tens • 2. ring → 100 → ones • 3. ring = multiplier • 4. ring = tolerance • With three value rings the previous example’s value of 470 Ω would be indicated as: • 1. ring = yellow → 40 • 2. ring = purple → 7 • 3. ring = brown → 101 → multiply by ten, ”add one zero” Resistor, schematic symbol

Europe

United States Adjustable resistor • A resistor might have a value that changes • Adjustable resistor • For instance , trimmers and faders are manually adjustable resistors • Heat dependent resistors () and light sensitive resistors (photoresistor, LDR) also exist • Usually three terminals • Between the left and right terminals the nominal value can always be found • The resistance between the center terminal and the outer terminals varies between 0 Ω and the nominal (maximum) resistance Potentiometer, Potentiometer, illustration

outer terminals

center terminal (shaft)

Rcl Rcr=Rnom-Rcl

Rnom Adjustable resistor, schematic symbol

Europe

United States Adjustable resistor, schematic symbol

light sensitive resistor Capacitor, ceramic Capacitor, electrolyte Capacitor • The main feature of a capacitor is to temporarily store electric energy when connected to a direct voltage source • A capacitor connected to a direct voltage source takes a while to charge and can then release the energy back to the circuit by discharging • A capacitor charges when it contains less electric energy than the rest or the circuit • A capacitor discharges when it contains more energy than the rest of the circuit • Some can store energy for very long times • Caution needed when operating high power and high voltage capacitors Capacitor • A capacitor consists of two pieces of conductive material that are attached to electrode plates • Between the plates there is a layer of slightly isolating material, which is called the dielectric • The dielectric can be solid material or a paste but also a liquid, jelly ,a gas or a vacuum • The most common dielectrics are metal foil or plated plastic foils Capacitor • When a capacitor is connected to a direct voltage source the electrode plates are charged with equal but opposite charges • This charge stays in the capacitor and starts to discharge when the voltage source is removed Capacitor, illustration

+ - Capacitors • Capacitors can be roughly divided into non-polarised (ceramic, polyester and tantalum capacitors) and polarised (electrolyte capacitors) • Non-polarised capacitors can be connected either way in the circuit but the polarised capacitors have a positive terminal () and a negative terminal () Capacitor, schematic symbol

non-polarised

+

polarised Diode Diodi • The diode is a passive component that has a key feature of letting the electric current pass in one direction (forward) and prevent it in the other direction (reverse) • This ”one way structure” is obtained by using charged materials inside the diode • The diode has two terminals • Positive, anode; negative, cathode • When the anode connects to the positive voltage source, the diode is in the forward direction → current passes • When the cathode connects to the positive terminal, the diode is in the reverse direction → current is blocked • One key use of a diode is rectification • Alternating voltage is transformed into direct voltage • A blocking diode has a maximum voltage (threshold), that should not be exceeded and semiconductivity • A diode has two layers, which both are exposed to a reaction giving them a positive or a negative electric charge • The negative layer (N) has a supernumerous amount of electrons and the positive layer (P) has a lack of electrons (=supernumerous protons, or ”electron gaps”) • In the forward direction the electrons in the N-layer are rejected towards the layer boundary by the negative voltage → current passes through the diode • In the reverse direction the electrons are drawn away from the boundary Diode and semiconductivity

+ - - + + - - forward direction + + - + -

+ -

current

+ - - + - + + + - - reverse direction - + - + Diodes • Even though the diode has a reverse direction, it cannot prevent the current from passing if the voltage between the terminals is too big • The diode reaches its breaking point and burns useless • An exception to this are so called zener diodes, that have a feature of allowing the current to flow in the reverse direction above the threshold voltage without burning • Typically used for battery checking circuits Diode, schematic symbol

diode

Rectification with diodes

-in

+in -out -out +out +out

-in +in Light emitting diode, LED Light emitting diode, LED • A diode that emits light when connected in the forward direction • Like the diode, an LED has an anode and cathode terminal • Commonly can only pass a very low current (in the range of 20-50 mA) • High power LEDs are an exception to this LED, schematic symbol Transistor Transistor • A semiconductor, that has a key feature of amplifying the flow of current or to the current on and off • Most commonly are either bipolar or unijunction transistors • Like a diode a transistor contains multiple layers that have an electric charge Bipolar transistor • A bipolar transistor has three terminals and three semiconductive layers • NPN → two negative layers with a positive layer between them • PNP → two positive layers with a negative layer between them • The terminals of a transistor are called base (B), collector (C) and emitter (E) • The base is located in the centre with the collector and emitter around it on the edges Bipolar transistor, NPN • When the emitter connects to a negative voltage this pushes the electrons in the emitter towards the emitter- base boundary • When a positive voltage is applied to the base it draws the electrons from the emitter and makes them ”jump” over to the collector that has a positive voltage • The base and collector voltages can be different • When electrons travel from the emitter to the collector the current passes from the collector to the emitter Bipolar transistor, NPN

E B C

- - -

- - - - + - - - -

current Bipolar transistor, PNP • The emitter connects to a positive voltage and the base and collector connect to a negative voltage • The negative charge of the base draws the ”electron gaps” from the emitter to the boundary • The negative voltage of the collector draws the electron gaps • Current flows from the emitter to the collector Bipolar transistor, PNP

E B C

+ + +

+ + + + - + + + +

current Bipolar transistor, schematic symbol

C

B NPN C

E B PNP

E Unijunction transistor • A special transistor with three terminals but only two semiconductive layers • The emitter, which has its own layer, commonly N • The two remaining terminals both are bases with a joint layer, typically P • When the emitter does not connect to a voltage the resistance between the two bases is relatively big → no current between the base terminals • When the emitter connects to a positive voltage it causes a rapid current increase between the bases Unijunction transistor

B2 B1

E

B2 B1

E Unijunction transistor, schematic symbol

B2

E

B1 Operational , IC Operational amplifier • Also called IC () • An advanced active component that has many terminals and various functions • Can be used for amplifying signals, timing, logical operations and many other functions Operational amplifier • The amount of terminals ranges from 4 → and they all have a specified function and have to connected properly • Somewhere on the IC there is a symbol indicating the ”top” edge of the circuit (colour spot or a semicircular groove) • When the top edge is pointing up the top left pin always is number 1 • The pin number increases downwards along the left edge and then jumps to the bottom right pin and increases upwards the right edge Operational amplifier, IC

1 8 1 16 2 7 2 15 3 6 3 14 4 5 4 13 5 12 6 11 7 10 8 9 , push buttons Switches, push buttons • Simple components that are only meant for opening and closing a circuit • A switch latches to its position, a push button needs constant pressing / pushing • May have two or more terminals Switches, push buttons, schematic symbols

Switch Push button • The operation of a is based on a phenomenon called inductance • A piece of material in an electric field tries to reject any changes in its own electromagnetic field • A transformer usually has a core (”heart”) made of conductive material (cast iron or other metal) • On two sides of the core there is copper wound around the core • These coilings are referred to as the primary and secondary side Transformers • When there is a current in the primary coil it causes a magnetic field to appear in the middle of the coil (core) • This magnetic flow is induced to the core of the transformer • This magnetic flow passes along the core to the secondary side • The magnetic flow in the core of the secondary coil induces an electric current in the secondary wire • The primary and secondary coils do not have a galvaninc (conductive) connection - they can be thought of being isolated from each other Transformers

• If the amount of wire rounds is N1 in the primary coil and N2 in the secondary coil then the voltage and current between the two sides have the following relation

• N1 / N2 = U1 / U2 = I2 / I1 • Direct current does not pass through the transformer since only an alternating current causes a change in the magnetic field in the core and affects the secondary coil Transformer

Core

Magnetic flow

Primary current Secondary current

Primary coil Secondary coil Schematics • A schematic of a circuit is a graphic illustration of how the components connect to each other • The layout of the actual circuit does not necessarily resemble the schematic • Due to this a schematic may show wire crossings that some represent a connection and some don’t Schematics

Connection No connection Breadboard • A circuit board for trying out circuits without the need to solder • ”Connection dots” arranged in rows and columns • Components can often be inserted straight into the dots • Some dots have a default electric connection between them • Usually the dots on the same row are connected but dots on different rows aren’t • Rows on opposite sides of the ”middle gap” are not connected • Some breadboards have voltage railings on the sides of the board running for a longer distance Breadboard, illustration

Connection dot Electrical ”default connection”

Middle gap

Voltage railing Placing components (resistor) on a breadboard

Wrong

Right Seembling components to a circuit board Exercise 1: Simple schematic

1. What does the circuit do? 2. What is the downside of the circuit? How can it be improved? Exercise 1: Simple schematic

3. How can we calculate the resistor value desired?

Imax = 20 mA = 0,02 A

U = R x I U = Rmin x Imax U = 9V Rmin = U / Imax Rmin = 9 V / 0,02 A Rmin = 450 Ω Exercise: Simple schematic

470Ω Exercise: Assemble this circuit on the breadboard Soldering needed: attach pieces of connection wire on the switch

470Ω Exercise 1: What does the circuit do?

470 Ω 100 kΩ

9 V

N/C Exercise 1: Assemble circuit on the breadboard Soldering needed: attach pieces of connection wire on the switch, push button and potentiometer terminals

470 Ω 10 kΩ

9 V

N/C Exercise: Assemble this circuit on the copper strip board

470Ω Exercise 2

+5-15V

10 kΩ 8 4 7

1 µF 56 6 kΩ NE555 3 2 1 5 8 0,01 µF Ω 0,01 µF

0 V