Common electronic components Electronics Klas Granqvist Akun Tehdas / Oy Aku’s Factory Ltd Electronics • 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 resistor 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 capacitor 100 µF / 16 V: 0,15 € • 2 pcs ceramic capacitor 0,47 µF: 0,30 € (total) • 2 pcs diode 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 Resistors Resistor • A small passive component that has a key feature of resisting the flow of an electric current • 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 (transistor, 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 potentiometers, trimmers and faders are manually adjustable resistors • Heat dependent resistors (thermistor) and light sensitive resistors (photoresistor, LDR) also exist • Usually three terminals • Between the left and right terminals the nominal potentiometer 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, trimmer 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 capacitors 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 (anode) and a negative terminal (cathode) Capacitor, schematic symbol non-polarised + polarised Diode Diodi • The diode is a passive semiconductor 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 Diodes 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 zener 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 switch the current on and off • Most commonly