BASIC ELECTRONIC EXPERIMENTS MODEL PK-101 TRANSFORMS ANY STANDARD BREADBOARD INTO AN ELECTRONIC LEARNING CENTER! Perform 50 Experiments! Build an Electronic Keyboard, Electronic Kazoo, Battery Tester, Finger Touch Lamp, Metal Detector, Burglar and Water Alarms, a Siren, a Magnetic Bridge, and a whole lot more! No soldering or tools required, all parts are included! (Requires a breadboard and a 9V battery or power supply.) Elenco Electronics, Inc., USA Copyright © 1999 Elenco Electronics, Inc.
In this booklet you will learn: • The basic principles of electronics. • How to build circuits using a breadboard. • How all of the basic electronic components work and how to read their values. • How to read electronic schematics. • How to design and troubleshoot basic electronic circuits. • How to change the performance of electronic circuits by changing component values within the circuit.
PARTS LIST Quantity Part Number 1 1 1 1 1 1 1 1 1 1 1 1 1 3 2 1 1 1 1 1 134700 141000 143300 151000 153300 161000 171000 191549 235018 244780 271045 281044 314148 323904 350002 442100 540100 590098 590102 - Description 470Ω Resistor, 0.25W 1kΩ Resistor, 0.25W 3.3kΩ Resistor, 0.25W 10kΩ Resistor, 0.25W 33kΩ Resistor, 0.25W 100kΩ Resistor, 0.25W 1MΩ Resistor, 0.25W 50kΩ Variable Resistor, lay-down, with dial 0.005µF Disc Capacitor 0.
INTRODUCTION TO BASIC COMPONENTS Welcome to the exciting world of Electronics! Before starting the first experiment, let’s learn about some of the basic electronic components. Electricity is a flow of sub-atomic (very, very, very, small) particles, called electrons. The electrons move from atom to atom when an electrical charge is applied across the material.
The Resistor: Why is the water pipe that goes to your kitchen faucet smaller than the one that comes to your house from the water company? And why is it much smaller than the main water line that supplies water to your entire town? Because you don’t need so much water. The pipe size limits the water flow to what you actually need. Electricity works in a similar manner, except that wires have so little resistance that they would have to be very, very thin to limit the flow of electricity.
The holes are connected together as follows: • There are many columns of 5 holes each. The 5 holes within each column are electrically connected together, but the columns are not electrically connected to each other. This makes 126 columns of 5 holes each. Note that “electrically connected together” means that there is a wire within the breadboard connecting the 5 holes.
After using your kit for a while, some of the wire ends may break off. If so, you should remove about 3/8 inch of insulation from the broken end with a wire stripper or scissors. Before You Begin: The rows of the breadboard are marked with letters (some rows are marked “+” and “–”) and the columns are marked by numbers, this allows each hole to be identified individually. We will use this notation to smoothly guide you through the experiments.
EXPERIMENT #1: The Light Bulb First, decide if you will use a 9V battery (alkaline is best) or the adjustable power supply that is part of the XK-150, XK-550, and XK-700 Trainers. If using a battery then snap it into its clip. Always remove the battery from its clip if you won’t be using your PK-101 for a while. Insert the red wire from the battery clip into hole j4 and the black wire into hole (–)3. 1 2 If using the adjustable power supply then turn it on and adjust it for 9V.
The Wiring Checklist and Wiring Diagram show you ONE way of connecting the circuit components using your breadboard. There are many other ways that are also correct. The important thing is that the electrical connections are as shown in the schematic (see below). Example of Inserting the Resistor Press the switch and the LED lights up, and turns off when you release the switch. The LED converts electrical energy into light, like the light bulbs in your home.
MORE ABOUT RESISTORS Ohm’s Law: You just observed that when you have less resistance in the circuit, more current flows (making the LED brighter). The relationship between voltage, current, and resistance is known as Ohm’s Law (after George Ohm who discovered it in 1828): Voltage Current = ____________ Resistance Resistance: Just what is Resistance? Take your hands and rub them together very fast. Your hands should feel warm. The friction between your hands converts your effort into heat.
The Variable Resistor: We talked about how a switch is used to turn the electricity on and off just like a valve is used to turn the water on and off. But there are many times when you want some water but don’t need all that the pipe can deliver, so you control the water by adjusting an opening in the pipe with a faucet. Unfortunately, you can’t adjust the thickness of an already thin wire.
EXPERIMENT #2: THE BRIGHTNESS CONTROL Remove the 10kΩ resistor used in Experiment #1; the other parts are used here. Insert the new parts according to the Wiring Checklist below. Press the switch and the LED lights up (it may be dim). Now hold the switch closed with one hand and turn the dial on the variable resistor with the other. When the dial is turned to the left, the resistance in the circuit is low and the LED is bright because a large current flows.
EXPERIMENT #3: RESISTORS IN SERIES Remove the resistors used in Experiment #2; the other parts are used here. Insert the new parts according to the Wiring Checklist and press the switch. The LED is on but is very dim (this will be easier to see if you wrap your hand near the LED to keep the room lights from shining on it). Take a look at the schematic. There is a low 3.3kΩ resistor and a high 100kΩ resistor in series (one after another).
EXPERIMENT #4: PARALLEL PIPES Remove the resistors used in Experiment #3; the other parts are used here. Insert the new parts according to the Wiring Checklist. Take a look at the schematic. There is a low 3.3kΩ resistor and a high 100kΩ resistor in parallel (connected between the same points in the circuit). How bright do you think the LED will be? Press the switch and see if you are right. The LED is bright, so most of the current must be flowing through the smaller 3.3kΩ resistor.
EXPERIMENT 5: COMPARISON OF PARALLEL CURRENTS Since we have two resistors in parallel and a second LED that is not being used, let’s modify the last circuit to match the schematic below. It’s basically the same circuit but instead of just parallel resistors there are parallel resistor-LED circuits. Remove the resistors used in Experiment #4; the other parts are used here. Insert the new parts according to the Wiring Checklist.
EXPERIMENT #6: COMBINED CIRCUIT Let’s combine everything we’ve done so far. Remove the resistors used in Experiment #3; the other parts are used here. Insert the new parts and wires according to the Wiring Checklist. Before pressing the switch, take a look at the schematic and think about what will happen as you turn the dial on the variable resistor (we’ll abbreviate this to VR). Now press the switch with one hand and turn the dial with the other to see if you were right.
EXPERIMENT #7: WATER DETECTOR You’ve seen how electricity flows through copper wires easily and how carbon resists the flow. How well does water pass electricity? Let’s find out. Connect the parts and wires according to the Wiring Checklist and take a look at the schematic. There isn’t a switch this time, so just disconnect one of the wires if you want to turn the circuit off. Notice that the Wiring Checklist leaves 2 wires unconnected.
INTRODUCTION TO CAPACITORS Capacitors: Capacitors are electrical components that can store electrical pressure (voltage) for periods of time. When a capacitor has a difference in voltage (electrical pressure) across it, it is said to be charged. A capacitor is charged by having a one-way current flow through it for a short period of time. It can be discharged by letting a current flow in the opposite direction out of the capacitor.
Similarly, capacitors are described by their capacity for holding electric charge, called their Capacitance, and their ability to withstand electric pressure (voltage) without damage. Although there are many different types of capacitors made using many different materials, their basic construction is the same. The wires (leads) connect to two or more metal plates that are separated by high resistance materials called dielectrics.
EXPERIMENT #8: SLOW LIGHT BULB Starting with this experiment, we will no longer show you the Parts List or the Wiring Checklist. Refer back to the previous experiments if you feel you need more practice in wiring the circuits. Refer back to page 10 if you need to review the resistor color code. Connect the circuit according to the schematic and Wiring Diagram and press the switch several times.
EXPERIMENT #9: SMALL DOMINATES LARGE - CAPACITORS IN SERIES Take a look at the schematic, it is almost the same circuit as the last experiment except that now there are two capacitors in series. What do you think will happen? Connect the circuit according to the schematic and Wiring Diagram and press the switch several times to see if you are right.
EXPERIMENT #10: LARGE DOMINATES SMALL - CAPACITORS IN PARALLEL Now you have capacitors in parallel, and you can probably predict what will happen. If not, just think about the last experiment and about how resistors in parallel combine, or think in terms of the water diagram again. Connect the circuit according to the schematic and Wiring Diagram and press the switch several times to see.
EXPERIMENT #11: MAKE YOUR OWN BATTERY Connect the circuit according to the schematic and Wiring Diagram. Note that one side of the battery and resistor are unconnected and there is a wire connected only to the 100µF capacitor. At this time no current will flow because nothing is connected to the battery.
TEST YOUR KNOWLEDGE #1 1. __________ are the particles that flow between atoms as part of an electric current. 2. A __________ circuit occurs when wires or components from different parts of the circuit accidentally connect. 3. A __________ produces electricity using a chemical reaction. 4. To decrease the current in a circuit you may decrease the voltage or __________ the resistance. 5.
EXPERIMENT #12: ONE - WAY CURRENT Your PK-101 includes one diode, a 1N4148, which is a standard diode widely used in industry. Connect the circuit and press the switch, the LED lights up. The diode’s turn-on voltage of 0.7V is easily exceeded and the diode has little effect on the circuit. Now reverse the wires to the diode and try again, nothing happens.
EXPERIMENT #13: ONE-WAY LIGHT BULBS Diodes made of Gallium Arsenide need a higher voltage across them to turn on, usually about 1.5V This turn-on energy is so high that light is generated when current flows through the diode. These diodes are the light emitting diodes that you have been using. To demonstrate this, connect the circuit below (note that the two LEDs will be referred to as “left” and “right”). Touch the loose wire to the battery and watch the left LED.
INTRODUCTION TO TRANSISTORS The Transistor: The transistor was first developed in 1949 at Bell Telephone Laboratories, the name being derived from “transfer resistor”. It has since transformed the world. Did you ever hear of something called a vacuum tube? They are large and can be found in old electronic equipment and in museums. They are seldom used today and few engineers even study them now. They were replaced by transistors, which are much smaller and more reliable.
EXPERIMENT #14: THE ELECTRONIC SWITCH Your PK-101 includes three transistors which are all type 2N3904 NPN Bipolar Junction Transistors. Connect the circuit according to the schematic and Wiring Diagram. Although there is a closed circuit with the battery, 1kΩ, LED, and transistor, no current will flow since the transistor is acting like an open circuit (with no base current the lever arm remains shut).
EXPERIMENT #16: THE SUBSTITUTE Look again at the water pipe analogy for the transistor, the lever pivot: What would happen if the base and collector were connected together? Once there is enough pressure to overcome the spring in check valve DE (0.7V) there would be only slight resistance and no current gain. This situation should sound familiar since this is exactly how a diode operates. When the base and collector of a transistor are connected together the transistor becomes a diode.
EXPERIMENT #17: STANDARD TRANSISTOR BIASING CIRCUIT Connect the circuit and press the switch while turning the variable resistor from right to left (from 0Ω to 50kΩ). The 100kΩ and variable 50kΩ are a voltage divider that sets the voltage at the transistor base. If this voltage is less than 0.7V then the transistor will be off and no current will flow through the LED. As the base voltage increases above 0.
EXPERIMENT #18: VERY SLOW LIGHT BULB Connect the circuit and press the switch, hold it down for several seconds. The LED will slowly light up. Release the switch and the LED will slowly go dark. When you first press the switch all of the current flowing through the 100kΩ resistor goes to charge up the capacitor, the transistor and LED will be off. When the capacitor voltage rises to 0.7V the transistor will first turn on and the LED will turn on.
EXPERIMENT #19: THE DARLINGTON This circuit is very similar to the last one. Connect the components and press the switch, hold it down for several seconds. The LED will slowly light up. Release the switch and the LED stays lit. Take a look at the schematic. All the current flowing through the emitter of the left transistor will flow to the base of the right transistor. So the current flowing into the base of the left transistor will be amplified twice, once by each transistor.
EXPERIMENT #21: THE ONE FINGER TOUCH LAMP Actually, the touch lamps you see in stores only need to be touched by one finger to light, not two. So let’s see if we can improve the last circuit to only need one finger. Connect the circuit, the only changes from the last experiment are the addition of the 1kΩ and 10kΩ resistors. These two resistors plug into adjacent (but not connected) holes g10 and g11.
EXPERIMENT #22: THE VOLTMETER Make sure you have a strong 9V battery for this experiment. Connect the circuit according to the Wiring Diagram and schematic, connect the battery last since this will turn on the circuit. And be sure to disconnect the battery (or turn off your power supply) when you’re not using the circuit to avoid draining the battery.
(Note positions of flat sides) 35 33kΩ 470Ω 10 kΩ +9V
EXPERIMENT #23: 1.5 VOLT BATTERY TESTER Make sure you have a strong 9V battery for this experiment. Connect the circuit, and connect the battery last since this will turn on the circuit. And be sure to disconnect the battery when you’re not using the circuit to avoid draining the battery. This circuit is a variation of the differential pair configuration used in Experiment 22, you will use it to test your 1.5V batteries. Take any 1.
EXPERIMENT #24: 9 VOLT BATTERY TESTER Make sure you have a strong 9V battery for this experiment. Connect the circuit, and connect the wire to the battery last since this will turn on the circuit. And be sure to disconnect this battery wire when you’re not using the circuit to avoid draining the battery. This time you will measure 9V batteries, just like the one you may be using to power your PK-101. Take the battery you want to test and hold it between the loose wires (the 3.
EXPERIMENT #25: BATTERY IMMUNIZER Connect the circuit according to the Wiring Diagram and schematic. Note that the collectors of the center and right transistors are not connected although their wires cross over each other in the schematic. Connect the loose wire to (+)18 or any of the (+) holes in the same row (which are connected to the battery); the LED is bright.
EXPERIMENT #26: THE ANTI-CAPACITOR Recall that capacitors blocked direct current (DC) but passed alternating current (AC). Take a look at Experiment 8 again and remember that it took time to light the LED because you had to charge the capacitor first; the capacitor passed the initial current surge through to ground (the negative side of the battery) but blocked the current once it stabilized, forcing it to go through the LED.
The Inductor: The inductor can best be described as electrical momentum (momentum is the power a moving object has). In our water pipe analogy the inductor can be thought of as a very long hose wrapped around itself many times as shown here: LARGE HOSE FILLED WITH WATER WATER PIPE PLUNGER Since the hose is long it contains many gallons of water. When pressure is applied to one end of the hose with a plunger the water would not start to move instantly, it would take time to get the water moving.
If you wrap two wires from different circuits around different ends of an iron bar then a current flowing through the wire from the first circuit will magnetically create a current in the wire from the second circuit! If the second coil has twice as many turns (more magnetic linkage) as the first coil then the second coil will have twice the voltage but half the current as the first coil. A device like this is called a transformer. Your PK-101 includes one.
EXPERIMENT #27: THE MAGNETIC BRIDGE Connect the circuit and press the switch several times. LED-left blinks when the switch is pressed and LED-right blinks when the switch is released. Although the LED may blink in the same manner as the last experiment, the method is quite different. There is no wire connection across the transformer, its DC resistance is very high.
EXPERIMENT #28: THE LIGHTHOUSE Connect the circuit. Notice that the transformer is being used as two coils (inductors) here. Also notice that two transformer taps are not connected although their wires cross in the schematic. Press the switch and hold it down for a while. The LED blinks every few seconds, like a tiny lighthouse! Notice that the LED blinks at a constant rate. This circuit is called an oscillator. It uses feedback.
EXPERIMENT #29: ELECTRONIC SOUND Now it’s time to make some noise. To do this we need a speaker. A speaker converts electrical energy into sound. It does this by using the energy of an AC electrical signal to create mechanical vibrations. These vibrations create variations in air pressure, called sound waves, which travel across the room. You “hear” sound when your ears feel these air pressure variations.
.005µF SPEAKER +9V S 473 µF 100µ DISC CAPACITORS 473 marking = 0.047µF 502 marking = 0.005µF µF 10µ - 45 3.
EXPERIMENT #30: THE ALARM This circuit is unusual in that you turn it on by disconnecting a wire and turn it off by connecting the wire. Connect the circuit, including a long wire as the “trip” wire. Notice that there is no sound. Now disconnect the trip wire and you hear a sound, an alarm. This type of circuit is used to detect burglars or other intruders.
EXPERIMENT #31: MORSE CODE The forerunner of today’s telephone system was the telegraph, which was widely used in the latter half of the 19th century. It only had two states − on or off (that is, transmitting or not transmitting), and could not send the range of frequencies contain in human voices or music. A code was developed to send information over long distances using this system and a sequence of dots and dashes (short or long transmit bursts). It was named Morse Code after its inventor.
EXPERIMENT #32: SIREN Connect the circuit and press the switch. It makes a siren sound. You saw earlier how you could change the frequency (pitch) of the oscillator by changing the oscillator’s resistance. Well this is basically the same oscillator circuit you’ve been using except that now we are electronically varying the oscillator’s resistance. The large 1MΩ resistor and 10µf capacitor cause the base voltage (and hence base current) on transistor NPNleft to rise slowly.
EXPERIMENT #33: ELECTRONIC RAIN Connect the circuit and press the switch. You hear a sound like raindrops. The variable resistor (VR) knob controls the rain, turn it to the right to make a drizzle and turn to the left to make the rain come pouring down. If you find it inconvenient to turn the VR knob while pressing the switch then just connect a wire across the switch.
EXPERIMENT #34: THE SPACE GUN Connect the circuit and press the switch several times quickly. You hear a sound like a space gun in the movies. You can adjust the “gun” sound using the variable resistor. If you find it inconvenient to turn the VR knob while pressing the switch then just connect a wire across the switch.
EXPERIMENT #35: ELECTRONIC NOISEMAKER Connect the circuit, connecting the battery last since it will turn the circuit on. Press the switch several times quickly. Then turn the variable resistor knob to change the frequency of the sounds. Do you understand what’s happening when you press the switch? You increase the oscillator capacitance by putting the 0.005µF in parallel with the 0.047µF, and this lowers the oscillator frequency. As usual you can experiment with changing component values if you like. .
EXPERIMENT #36: DRAWING RESISTORS You need some more parts to do this experiment, so you’re going to draw them. Take a pencil (No. 2 lead is best but other types will also work), SHARPEN IT, and fill in the 4 rectangles you see below. You will get better results if you place a hard, flat surface between this page and the rest of this booklet while you are drawing.
+9V S 473 P 10kΩ 3.
EXPERIMENT #37: ELECTRONIC KAZOO Now it’s time to make your own music. This experiment will use the (almost) same circuit as the last one, so there is no schematic or Wiring Checklist. The only difference is that you will draw a new shape. A Kazoo is a musical instrument that is like a one-note flute, and you change the pitch (frequency) of the sound by moving a plunger up and down inside a tube. As before, take a pencil (No.
EXPERIMENT #38: ELECTRONIC KEYBOARD This experiment will use the (almost) same circuit as the last one, so there is no schematic or Wiring Checklist. The only difference is that you will draw a new shape. As before, take a pencil (No. 2 lead is best but other types will also work), SHARPEN IT again, and fill in the shape you see below. For best results, SHARPEN IT again, place a hard flat surface between this page and the rest of this booklet while you are drawing. Press hard (but don’t rip the paper).
EXPERIMENT #39: FUN WITH WATER Connect the circuit, initially the two loose wires are unconnected so there is no sound. Now touch each wire with fingers from different hands, you should hear a low-frequency sound. (Wetting your fingers with water or saliva will make better electrical contact). You are using your body as an electrical component, just as you did in Experiment 20 (Two Finger Touch Lamp). If you like you may make the sound louder by replacing the wire between a23 and a31 with a 3.
EXPERIMENT #40: BLINKING LIGHTS Take a look at the schematic. This circuit configuration is a type of oscillator called an astable multivibrator. What do you think it will do? Connect the circuit, noting that the transistor bases are not connected although their wires cross in the schematic. Initially set the variable resistor (VR) to its minimum value (turn it to the left). Press the switch and hold it down. One LED is on while the other is off, and they change about every second.
EXPERIMENT #41: NOISY BLINKER This circuit is similar to the last one. Connect the circuit (noting that the transistor bases are not connected although their wires cross in the schematic). Press the switch and hold it down. The LED lights and you hear sound from the speaker. Turn the knob on the variable resistor and the frequency of the sound changes. Can you tell what the LED is really doing? It is actually blinking about 500 times a second, but to your eyes it appears as a blur or just dim.
EXPERIMENT #42: ONE-SHOT Do you know what this circuit will do? Connect everything, then press the switch and release it. The LED is on for a few seconds and then goes out. What effect do you think changing the value of the variable resistor will have? Try it. The higher the resistance the longer the LED stays on. This circuit is a variation of the astable multivibrator and is called a one-shot multivibrator, because the LED comes on once each time the switch is pressed.
EXPERIMENT #43: ALARM WITH SHUT-OFF TIMER Let’s demonstrate a use for the timer circuit you just built by combining it with Experiment 30, the Alarm. Connect the circuit (noting that the transistor bases and transformer signals are not connected although their wires cross in the schematic). Connect the alarm trip wire and then connect the battery wire to turn the circuit on. Press the switch once. Now disconnect the trip wire to activate the alarm. The alarm stays on for a few seconds and then goes off.
EXPERIMENT #44: THE FLIP - FLOP This circuit is yet another variation of the basic multivibrator configuration. Connect the circuit. One LED will be on, the other off. Take the loose wire and touch it to the base of the transistor that is on (holes b15 and a27 will do, or you can touch the resistor leads connected to these points). That transistor turns off and the other turns on. Do this a few more times until you see that touching the “on” transistor base “flips” the transistors and the LEDs.
EXPERIMENT #45: FINGER TOUCH LAMP WITH MEMORY Instead of using the wire to flip-flop the LED you may also use your fingers as you did in Experiment 20, the Two Finger Touch Lamp. We’ll use almost the same circuit here as in the last experiment. Remove the loose wire and replace the right LED with a diode, because we don’t need two “lamps”. Wet two fingers and hold one on 9V (the (+) row of holes) while touching the other to one of the transistor bases.
EXPERIMENT #46: THIS OR THAT Now that you’re familiar with the flip-flop, let’s introduce some more digital circuits. Digital circuits are circuits that have only two states, such as high-voltage/low-voltage, on/off, yes/no, and true/false. Connect the circuit. Take a look at the schematic, it is very simple. Wires X and Y are considered to be digital inputs, so connect them to either the (+) row of holes (9V, or HIGH) or leave them unconnected (this is the same as connecting them to 0V, or LOW).
EXPERIMENT #47: NEITHER THIS NOR THAT Now let’s add on to the previous circuit. Everything from Experiment 46 remains in place, just add the new parts and wires shown in the schematic and Wiring Diagram. Test the four combinations of X and Y as before to determine the state of LED-right (ON or OFF), filling in the table at right: X LOW LOW HIGH HIGH Y LOW HIGH LOW HIGH LED-right This table shows that if neither X nor Y is HIGH then LED-right is ON. Hence, this configuration is called a NOR gate.
EXPERIMENT #48: THIS AND THAT Take a look at the schematic. Can you guess what kind of digital gate this is? We’ll use almost the same circuit here as in the last experiment. Remove the wire between holes a16 and a17, and the one between holes a19 and (–)19. Add a wire between holes a16 and a19. Also, remove the 100kΩ resistor, we’ll re-connect it later.
EXPERIMENT #49: AUDIO AND, NAND Using the LEDs for these truth tables probably seems a little boring. So let’s use an audio circuit to make a sound instead of turning on the LED. Connect the wires according to the schematic and Wiring Diagram. Can you tell which digital gate this circuit represents? Construct the truth table to find out. It is the NAND gate. If you use longer wires for X and Y and leave them connected HIGH then you have an alarm with two separate trip wires.
EXPERIMENT #50: LOGIC COMBINATION This last circuit is a combination of some of the other digital gates, and has 3 inputs. See if you can fill in the truth table by just looking at the schematic. Then connect the circuit, test all eight input combinations, and see if you were right.
TEST YOUR KNOWLEDGE #3 1. Adjusting the input to something based on what its output is doing is an example of __________. 2. A speaker converts electrical energy into __________ __________ variations, called sound waves. 3. An oscillator’s frequency __________ when you add resistance or capacitance. 4. A NOR gate followed by a NOT gate is the same as an __________ gate. 5. An AND gate followed by a NOT gate is the same as a __________ gate.
DEFINITION OF TERMS (Most of these are introduced and explained during the experiments.) AC.................................... Common abbreviation for alternating current. Alternating Current...... A current that is constantly changing. Amp................................. Shortened name for ampere. Ampere (A).................... The unit of measure for electric current. Commonly shortened to amp. Amplitude....................... Strength or level of something. Analogy..........................
Electronics..................... The science of electricity and its applications. Emitter............................ The output of an NPN bipolar junction transistor. Encode........................... To put a message into a format which is easier to transmit. Farad, (F)....................... The unit of measure for capacitance. Feedback....................... To adjust the input to something based on what its output is doing. Flip-Flop.........................
Primary........................... The larger of the two coils in a transformer. Printed Circuit Board... A board used for mounting electrical components. Components are connected using metal traces “printed” on the board instead of wires. Receiver......................... The device which is receiving a message (usually with radio). Resistance.....................
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