Page 1 ELECTRONIC PLAYGROUND and LEARNING CENTER MODEL EP-130 99 Washington Street Melrose, MA 02176 Phone 781-665-1400 Toll Free 1-800-517-8431 Visit us at www.TestEquipmentDepot.com Elenco Electronics, Inc. ® Wheeling, IL, USA Copyright © 2009 by Elenco ® Electronics, Inc. All rights reserved. 753039 No part of this book shall be reproduced by any means;...
Page 2: Table Of Contents
Important: If you encounter any problems with this kit, DO NOT RETURN TO RETAILER. Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Carpenter Ave. • Wheeling, IL 60090 U.S.A. WARNING: Always check your wiring before Batteries: turning on a circuit.
Page 3 VI. THE WORLD OF TRANSISTOR-TRANSISTOR LOGIC 64 93. LED Initials 94. Wake Up Siren 48. TTL Astable Multivibrator 95. Voice Activated LED 49. TTL Tone Generator 96. Logic Tester 50. Winking LEDs 51. A One-Shot TTL IX. MORE ADVENTURES WITH OPERATIONAL AMPLIFIERS 116 52.
Page 4: Before We Begin
BEFORE WE BEGIN Welcome to the exciting world of electronics! The Elenco ® EP-130 Electronic Playground Kit may be You’ll notice that we often refer to a Volt / Ohm Meter your first experience in electronics. This manual (VOM) for making measurements. A VOM, or describes 130 different experiments you can perform multimeter, is a device that measures voltage, with your kit.
Page 5: Making Wire Connections
MAKING WIRING CONNECTIONS The spring terminals and the pre-cut wires supplied Be sure that you only insert the exposed, shiny part with your lab kit make it a snap to wire together the of the wire into the spring terminal. If the plastic various projects.
Page 6 flow of electricity. They would be hard to handle and Capacitors: Capacitors can pass alternating current break easily. But the water flow through a large pipe (AC) signals while blocking direct current (DC) could also be limited by filling a section of the pipe signals.
Page 7 (marked Ge); they each have their own uses as we’ll Integrated Circuit: As you might already know, after explain later. the transistor was invented in the middle 1940’s, the next big breakthrough in electronics was the integrated circuit in the early 1960’s. The great advantage of ICs (as we call them) is that the equivalent of hundreds or even thousands of transistors, diodes, and resistors can be put into a...
Page 8 Antenna: The radio antenna is the cylindrical Speaker: A speaker converts electrical energy into component with a coil of fine wire wrapped around it. sound. It does this by using the energy of an AC The dark colored rod is made mostly of powdered electrical signal to create mechanical vibrations.
Page 9: Building Your First Project
Key: The Key is a very simple switch - press it and the circuit allows electricity to flow through it. Release it and there is a break in the circuit’s path, so the circuit is not complete. You will use the key in many circuits, most often in the signaling circuits (to send Morse code, and so on).
Page 10: Troubleshooting
TROUBLESHOOTING If you assemble each project according to its wiring 3. How about following the schematic diagram and sequence, you should have no problem getting the circuit explanation? As you progress in your projects to work properly. But if you do have a knowledge and understanding of electronics, you problem, you can usually find and correct it by using should be able to do some troubleshooting only by...
Page 11: Entertainment Circuits
I. ENTERTAINMENT CIRCUITS -11-...
Page 12: Electronic Woodpecker
EXPERIMENT #1: ELECTRONIC WOODPECKER Have you ever heard a red-headed woodpecker You can also try the 3V power supply (V is the chirping? Here is an electronic bird that sounds a abbreviation for volt or volts - the basic unit of little like a red-headed woodpecker.
Page 13: The Chirping Bird
EXPERIMENT #2: THE CHIRPING BIRD Here’s a circuit that imitates more of our feathered Notes: friends - you could say it mocks the mockingbird! Complete the circuit as shown below and slide the switch to position A to turn on the power. You won’t hear any sound from the speaker yet.
Page 14: Electronic Cat
EXPERIMENT #3: ELECTRONIC CAT Bothered by mice? And you don’t have a Notes: mousetrap? Try this instead - see if the sound of the electronic feline can keep those pests away. Follow the wiring sequence and drawing, and start the experiment with the switch set to B. Press the key and release it immediately.
Page 15: Sonic Fish Caller
EXPERIMENT #4: SONIC FISH CALLER Did you know that some marine animals or the 0.05μF capacitor. Be sure to keep notes of communicate with each other by sound? You’ve your results - and good fishing! Who knows, you probably heard that whales and porpoises might find the type of signal that attracts a whale! communicate by sound, but they’re not the only ones.
Page 16: Machine Gun Pulse Oscillator
EXPERIMENT #5: MACHINE GUN PULSE OSCILLATOR In this you’ll build a circuit that engineers call a When you finish wiring, press the key to start the “pulse oscillator”. It makes sounds like a machine oscillator. Adjust the control (50kΩ variable resistor) gun.
Page 17: Electronic Motorcycle
EXPERIMENT #6: ELECTRONIC MOTORCYCLE Ever try steering a motorcycle (OK, maybe a Notes: bicycle) with just four fingers? That’s dangerous on a real motorcycle, but it’s a lot of fun in this electronic version. To use this project, connect the components according to the wiring sequence.
Page 18: Two-Tone Patrol Car Siren
EXPERIMENT #7: TWO-TONE PATROL CAR SIREN Here is a loud siren that is so much like the real Notes: sirens on some police cars and ambulances, that you may have to be careful not to confuse your neighbors. The initial tone is high, but when you close the key, the tone lowers.
Page 19: Electronic Siren
EXPERIMENT #8: ELECTRONIC SIREN Here’s another siren - don’t be surprised if this Notes: becomes the most popular circuit in this entire kit. This circuit sounds even more like a real siren on a police car! After completing the wiring, press the key.
Page 20: Electronic Metronome
EXPERIMENT #9: ELECTRONIC METRONOME Here’s a circuit you might find useful if you’re Notes: learning to play a musical instrument. This is an electronic version of the metronome used by music students everywhere. Press the key. You’ll hear a sound from the speaker at fixed intervals.
Page 21: Electronic Grandfather Clock
EXPERIMENT #10: ELECTRONIC GRANDFATHER CLOCK Do you want to perk up the ears of some of your Notes: elders? Anyone who has lived in a house with a grandfather clock will think you have one when they hear this project. The circuit produces clicks at approximately one second intervals.
Page 22: Light-Controlled Electronic Harp
EXPERIMENT #11: LIGHT-CONTROLLED ELECTRONIC HARP You are going to play musical tunes by waving your Notes: hand over the board without touching it! Magic? Incredible? The tones change with the amount of light that reaches the CdS cell. Under a bright light, the tone is high.
Page 23: Horror Movie Sound Effects
EXPERIMENT #12: HORROR MOVIE SOUND EFFECTS The sound that this circuit produces will remind you Notes: of the scary music you hear in horror movies. After wiring the project, use your special light shield and your hand to change the amount of light that falls on the CdS cell.
Page 24: Strobe Light
EXPERIMENT #13: STROBE LIGHT Here’s an oscillator circuit that doesn’t use the Notes: speaker or earphone - you don’t hear its output. Instead, you see the output from an LED. This gives you an idea of how large strobe lights work. Press the key and watch LED 1.
Page 25: Rapid Led Display Switching (Persistence Of Vision Test)
EXPERIMENT #14: RAPID LED DISPLAY SWITCHING (PERSISTENCE OF VISION TEST) This is a control circuit that produces short pulses. You might want to try different values of capacitors When you close the key, the LED display shows 1 and see their effects, but don’t use a capacitor value for an instant and then goes off, even if you keep higher than 10μF or the transistor might be pressing the key.
Page 26: Basic Semiconductor & Components Circuits
II. BASIC SEMICONDUCTOR AND COMPONENTS CIRCUITS -26-...
Page 27: A Big Change
A BIG CHANGE Until now, you have had drawings of your kit, in addition You’ll notice on the schematics that some lines cross to the wiring sequences, to guide you in making wiring each other and there’s a dot at the point where they connections.
Page 28: Capacitor Discharge/High Voltage Generator
EXPERIMENT #15: CAPACITOR DISCHARGE / HIGH VOLTAGE GENERATOR This circuit shows how single pulses of high voltage Notes: electric energy are generated when a charged capacitor is suddenly discharged through a transformer. (Capacitor-discharge automobile ignition systems use this same type of reaction.) The operation of this circuit is simple, but the concepts involved are important to understanding more...
Page 29: Capacitors In Series & Parallel
EXPERIMENT #16: CAPACITORS IN SERIES AND PARALLEL The capacitors are some of the handiest items in You hear a high-pitched sound from the speaker. your kit. They can store electricity, smooth out This is because the 0.05μF and 0.01μF capacitors pulsing electricity into a steady flow and let some are not connected in series - current flows from one electric current flow while blocking other current.
Page 30: Resistors In Series & Parallel
EXPERIMENT #17: RESISTORS IN SERIES AND PARALLEL In this project, you will see what happens when you in a series connection. You must multiply the values connect resistors in series and in parallel. When you together, then divide the product by the sum of the finish wiring, you can see LED-1 on the panel flash values.
Page 31: Light Dimmer
EXPERIMENT #18: LIGHT DIMMER In this project, you use a capacitor’s charging and Now go back to project 8 (Electronic Siren) and see discharging to dim a light (an LED in this case). if you can figure out why the siren sound goes from When you finish the wiring, set the switch to A.
Page 32: Transistor Switcher
EXPERIMENT #19: TRANSISTOR SWITCHER This is designed to help you study the switching Now change the resistors to 10kΩ and press the action of the transistors in turning on the LED. You key. Use terminals 81 and 82, and terminals 83 and will use two different transistors –...
Page 33: Transistor Circuit Action
EXPERIMENT #20: TRANSISTOR CIRCUIT ACTION A transistor has three connections; one of these (the Notes: base) is used to control the current between the other two connections. Remember this important rule for transistors: a transistor turns on when a certain voltage is applied to its base. Positive voltage turns on an NPN type transistor.
Page 34: Sound Amplifier
EXPERIMENT #21: SOUND AMPLIFIER This circuit is a strong two-transistor amplifier. An This establishment of an electric charge using a amplifier uses a small signal to control or produce a magnetic field is called induction. Go back to Project large signal. This amplifier is similar to an early 15 (Capacitor Discharge / High Voltage Generator) model transistor hearing aid amplifier.
Page 35: Flip-Flop Multivibrator With Led Display
EXPERIMENT #22: FLIP-FLOP MULTIVIBRATOR WITH LED DISPLAY How about some rest? Here’s another circuit for Notes: entertainment. This circuit flashes the numbers 1 and 2 on the display. You might be reminded of some neon signs with flashing, eye-catching advertisements on them. A circuit called a flip-flop controls the LED display in this project.
Page 36: Iii. Led Digital Display Circuits
III. LED DIGITAL DISPLAY CIRCUITS -36-...
Page 37: Seven-Segment Led Digital Display Circuit
EXPERIMENT #23: SEVEN-SEGMENT LED DIGITAL DISPLAY CIRCUIT In this section, we perform some basic circuit Now try measuring the voltage in each resistor experiments with the LED display to learn how to attached to an LED segment. The resistors are all better use this component.
Page 38: Basic Led Display
EXPERIMENT #24: BASIC LED DISPLAY Now you will learn about a common-cathode, Notes: seven-segment, LED digital display. Common- cathode means that the seven LED display segments use one contact point – terminal 25 – as a common negative electrode. The LED must have (+) and (–) connections so that current can flow through it.
Page 39: Transistor Control Switching Of The Led Display
EXPERIMENT #25: TRANSISTOR CONTROL SWITCHING OF THE LED DISPLAY Now we’re getting down into the field of electronics. Notes: The explanations from now on will become a bit more difficult, and more interesting! This project shows how to control the LED display with transistors.
Page 40: Transistor, Cds Cell, And Led Display Circuit
EXPERIMENT #26: TRANSISTOR, CdS CELL AND LED DISPLAY CIRCUIT This project shows you how to turn on the LED Notes: using a transistor and a CdS cell. Think of the CdS cell as a resistor that changes its resistance with the amount of light that falls on it. In darkness the resistance is very high, around 5 megohms (MΩ, 5 million ohms);...
Page 41: Iv. A Tour Through Digital Circuits
IV. A TOUR THROUGH DIGITAL CIRCUITS -41-...
Page 42: Diode-Transistor Logic And With Led Display
EXPERIMENT #27: DIODE-TRANSISTOR LOGIC “AND” WITH LED DISPLAY Now let’s step into the world of digital circuits and When either or both inputs are low (that is, terminal learn some basics. First, a digital circuit is a circuit 126 and/or terminal 128 is connected to terminal that acts as a switch to turn different components on 119), positive voltage is applied to the PNP and off.
Page 43: Dtl Or Circuit With Led Display
EXPERIMENT #28: DTL “OR” CIRCUIT WITH LED DISPLAY This next logic circuit is a logic OR circuit. Can you Notes: guess how this circuit works? Remember the AND circuit produces logic high when both A and B inputs are high. The OR circuit produces logic high when A or B receives a logic high input.
Page 44: Dtl Nand Circuit With Led Display
EXPERIMENT #29: DTL “NAND” CIRCUIT WITH LED DISPLAY No, you cannot find the word NAND in your Notes: dictionary (unless it is an electronics or computer dictionary). This is a newly coined term that means an inverted, or a Non-AND function. It produces output conditions that are the opposite of the AND circuit’s output conditions.
Page 45: Dtl Exclusive Or Circuit
EXPERIMENT #30: DTL “EXCLUSIVE OR” CIRCUIT Don’t worry if you don’t know what exclusive OR Notes: means. An exclusive OR (abbreviated XOR) circuit provides a high output only when one or the other of its inputs is high. So, you can see that an XOR circuit produces a low output if both inputs are the same (high or low).
Page 46: Transistor Nor Circuit With Led Display
EXPERIMENT #31: TRANSISTOR “NOR” CIRCUIT WITH LED DISPLAY Now that you’ve built and learned about the NAND Notes: (inverted AND) circuit, it’s easy to determine what the NOR (inverted OR) circuit does. The display shows L when either terminal A or B is connected to terminal H (119).
Page 47: Transistor Flip-Flop Circuit
EXPERIMENT #32: TRANSISTOR “FLIP-FLOP” CIRCUIT What is a flip-flop? It is a kind of circuit that changes When the charge drops to a certain point, the back and forth between two states (on and off) at negative voltage from the 47kΩ resistor turns on certain intervals.
Page 48: Transistor Toggle Flip-Flop
EXPERIMENT #33: TRANSISTOR “TOGGLE FLIP-FLOP” A toggle switch is a switch that turns circuits on and Notes: off. Here we use the flip-flop circuit to work as a toggle switch. In the previous project, the circuit flipped and flopped automatically. In this project, the circuit does not change until you tell it to.
Page 49: More Adventures With Digital Circuits
V. MORE ADVENTURES WITH DIGITAL CIRCUITS -49-...
Page 50: Transistor-Transistor Logic Buffer Gate
EXPERIMENT #34: TRANSISTOR-TRANSISTOR LOGIC “BUFFER” GATE Did you ever wonder what happens when you start Refer to the schematic as you build this project. We adding digital circuits together, using the output of take the output from one NAND gate, and use it for one as the input of another? When you build this both inputs to the second (note the two inputs for project you’ll find out.
Page 51: Ttl Inverter Gate
EXPERIMENT #35: TTL “INVERTER” GATE An inverter is a circuit that has an output that is the Notes: opposite of its input. If the input is 1 (high), the output is 0 (low). If the input is 0, then the output is 1. Set the switch to A before you complete this project.
Page 52: Ttl And Gate
EXPERIMENT #36: TTL “AND” GATE Can you figure out how to make an AND gate using Notes: your kit’s NAND gates? Let’s experiment, to find out how. Leave the switch at B as you build this circuit. When you are finished, connect terminals 13 and 14 to turn the power on.
Page 53: Ttl Or Gate
EXPERIMENT #37: TTL “OR” GATE One of the nice things about the quad two-input We can make up AND, NOR, XOR, and NAND gates NAND IC is that we can combine the four NAND using the quad two-input IC. Can you figure out how gates to make up other logic circuits.
Page 54: Ttl Exclusive Or Gate
EXPERIMENT #38: TTL “EXCLUSIVE OR” GATE Since we’ve made up other digital circuits by Notes: combining NAND gates, it makes sense that we can make XOR gates as well. We can, as this circuit will show you. Set the switch to B before you complete this circuit. After you finish the wiring, connect terminals 13 and 14.
Page 55: Ttl Nor Gate
EXPERIMENT #39: TTL “NOR” GATE Try marking 0 and 1 inputs on the schematic as Notes: you’ve been doing with the past few projects and see how this circuit arrives at a 0 or a 1 output. Give it a good try, and don’t peek at the answer.
Page 56: Ttl Three-Input And Gate
EXPERIMENT #40: TTL “THREE-INPUT AND” GATE Although we’ve been using digital circuits that have This 1 output then goes to another NAND gate (see two inputs, that doesn’t mean we can’t have more it on the schematic?). There it makes up one input, than two inputs.
Page 57: Ttl And Enable Circuit
EXPERIMENT #41: TTL “AND” ENABLE CIRCUIT Our last project had a characteristic that could be a Notes: problem in some situations. LEDs 1 and 2 take turns lighting and turning off. We might want both LEDs to light and turn off together. Did you figure out how to make the LEDs do this when you experimented with the last project? This circuit shows you how.
Page 58: Ttl Or Enable Circuit
EXPERIMENT #42: TTL “OR” ENABLE CIRCUIT Have you figured out how to make an enable circuit Notes: using an OR gate? If so, here’s a chance to check your design against our OR enable circuit. As in the last two projects, a multivibrator provides input to the OR gate in this circuit.
Page 59: Ttl Nand Enable Circuit
EXPERIMENT #43: TTL “NAND” ENABLE CIRCUIT NAND gates can act as electronic sentries. If you LED 1 lights, but because both input signals to the don’t want a signal to be input into a part of the NAND are 1, the NAND’s output is 0, and LED 2 circuit, a NAND gate can be sure it is not.
Page 60: Ttl R-S Flip-Flop
EXPERIMENT #44: TTL “R-S FLIP-FLOP” No, R-S does not mean Radio Shack ® flip-flop. As Notes: we mentioned, earlier, flip-flop circuits are circuits that alternate between two states. Engineers often use flip-flop circuits to switch between high (1) and low (0) outputs. When the output is high, or on, we say the circuit is at set status (S).
Page 61: Toggle Flip-Flop Circuit Made From Nand Gate
EXPERIMENT #45: “TOGGLE FLIP-FLOP” CIRCUIT MADE FROM “NAND” GATE If you think the NAND gate is a very versatile circuit, Notes: you’re right! Here’s a toggle flip-flop circuit made from four NAND gates. Connect terminals 13 and 14 to turn the power on after you finish building this circuit.
Page 62: Ttl Line Selector
EXPERIMENT #46: TTL LINE SELECTOR It isn’t hard to think of situations where we might Notes: want to send input data to two or more different outputs. This project shows how we can use a network of NAND gates to help do just that. You can see that we use a multivibrator and three NAND gates in this circuit.
Page 63: Ttl Data Selector
EXPERIMENT #47: TTL DATA SELECTOR Our last projects let you see how data could be sent Computers and other highly advanced digital circuits to two or more different outputs. You can probably use a more complex version of these circuits. As you think of some situations where we might want (or probably suspect, switching from one input channel need) to do the opposite –...
Page 64: The World Of Transistor-Transistor Logic
VI. THE WORLD OF TRANSISTOR-TRANSISTOR LOGIC -64-...
Page 65: Ttl Astable Multivibrator
EXPERIMENT #48: TTL ASTABLE MULTIVIBRATOR Even multivibrator circuits can be made from NAND Notes: gates. This project is an example of an astable multivibrator – can you guess what astable means? Make a guess, and complete this project to see if you were right.
Page 66: Ttl Tone Generator
EXPERIMENT #49: TTL TONE GENERATOR We’ve been producing tones with audio oscillators Notes: for so long that it might seem as if there’s no other way to produce tones from electronic circuits. Not so – a multivibrator made from NAND gates does the job nicely.
Page 67: Winking Leds
EXPERIMENT #50: WINKING LEDS Complete the wiring sequence for this circuit and Notes: connect terminals 13 and 14 to turn on the power. You’ll see both LED 1 and LED 2 take turns going on and off. You can change the speed of the blinking by substituting different values for the 100μF capacitor.
Page 68: A One-Shot Ttl
EXPERIMENT #51: A ONE-SHOT TTL Does the term one-shot mean anything to you? (No, Notes: it’s not a nickname for a cowboy or a gun that holds just one bullet!) After you complete the wiring for this circuit, turn the switch to A to turn on the power.
Page 69: Transistor Timer With Ttl
EXPERIMENT #52: TRANSISTOR TIMER WITH TTL Here’s another type of one-shot circuit, but in this Notes: project you hear the effects of the multivibrator. You can see from the schematic that this project uses a combination of simple components and digital electronics.
Page 70: Buzzin' Led
EXPERIMENT #53: BUZZIN’ LED Here’s another circuit that uses both transistor and Notes: NAND type multivibrators. It allows you to see LED 1 light up at the same time you hear a sound through the earphone. When you finish building this project, connect the earphone to terminals 13 and 14 and set the switch to position A.
Page 71: Son Of Buzzin' Led
EXPERIMENT #54: SON OF BUZZIN’ LED Carefully compare the schematic for this project with Notes: the schematic for the last project. They are similar in many ways, but there’s an important difference. Do you see what it is? Better still, can you tell what effect the difference has on the project’s operation? Try to figure it out before you build this circuit.
Page 72: Set / Reset Buzzer
EXPERIMENT #55: SET/RESET BUZZER 1 Anything look familiar about the schematic for this Notes: project? This circuit uses an R-S flip-flop circuit made from NAND gates, similar to the circuit in Project 44 (“TTL R-S Flip-Flop”). After you finish building this project, set the switch to position A and press the key.
Page 73 EXPERIMENT #56: SET/RESET BUZZER 2 Here’s another version of the last project. This time Notes: we use a NAND multivibrator and an R-S flip-flop made with transistors. This circuit works like the last one. When you set the switch to B and press the key, you hear a sound in the earphone.
Page 74: Sound Machine
EXPERIMENT #57: SOUND MACHINE This digital sound project makes use of a circuit Notes: we’ve used in some earlier projects. Try to tell which circuit we’re talking about by looking at the schematic. While you’re looking for that certain circuit, why not listen to the sound this project makes? Because there are a lot of wiring steps, you need to take your time and check your work.
Page 75: Big Mouth
EXPERIMENT #58: BIG MOUTH Do you know someone who is a big mouth? (Or, Notes: have you been accused of being one?) This project lets you and your friends see who’s got the loudest voice. You can see how this project works by looking at the schematic.
Page 76: Shot In The Dark
EXPERIMENT #59: SHOT IN THE DARK Do you think you have good night vision? This last Good luck and may you become “the fastest project in this section is a game that lets you find out flashlight in the West!” how well you can see in the dark.
Page 77: Application Circuits Based On The Oscillator
VII. APPLICATION CIRCUITS BASED ON THE OSCILLATOR -77-...
Page 78: Variable R-C Oscillator
EXPERIMENT #60: VARIABLE R-C OSCILLATOR The “R-C” in this project’s name stands for Notes: resistance-capacitance. We’ve seen how varying resistance and capacitance can affect the pulsing action of an oscillator. This project lets us see the effects when we change the strengths of both resistors and capacitors.
Page 79: Oscillator With Turn-Off Delay
EXPERIMENT #61: OSCILLATOR WITH TURN-OFF DELAY We’ve seen how a capacitor’s charge/discharge Notes: cycle can be used to delay certain circuit operations. Now let’s delay the oscillator action in this project with a 470μF capacitor. When you press the key, the capacitor discharges. When you release the key, the capacitor begins to charge.
Page 80: Temperature-Sensitive Audio Oscillator
EXPERIMENT #62: TEMPERATURE-SENSITIVE AUDIO OSCILLATOR Did you know that a transistor changes its Notes: characteristics according to the temperature? This project will show you how temperature affects transistor action. Look at the schematic. The NPN transistor acts as a pulse oscillator. The voltage applied to its base is controlled by the 22kΩ...
Page 81: Two-Transistor, Directly-Connected Oscillator
EXPERIMENT #63: TWO-TRANSISTOR, DIRECTLY CONNECTED OSCILLATOR Now we will build an oscillator using two transistors Notes: connected directly to each other. As you have seen, there are many ways to make an oscillator. This way is simple compared to some. After completing the wiring, press the key.
Page 82: Push / Pull Square Wave Oscillator
EXPERIMENT #64: PUSH/PULL SQUARE WAVE OSCILLATOR In this project we will make a push/pull, square wave Notes: oscillator. This oscillator is called a push/pull because it uses two transistors that are connected to each other. They take turns operating so that while one transistor is “pushing,”...
Page 83: Pencil Lead Organ
EXPERIMENT #65: PENCIL LEAD ORGAN This project is an oscillator that is controlled in an Notes: unusual way: with a pencil mark! You have seen in other oscillator projects how changing the circuit’s resistance can change the sound that is produced. The resistors, like the ones in your kit, are made of a form of carbon, and so is pencil lead.
Page 84: Led Strobe Light
EXPERIMENT #66: LED STROBE LIGHT This circuit is an oscillator with a low frequency. So, Notes: you can see the LED lighting and turning off. The off time is longer than the on time, so you see short pulses of light with long periods between them. The wiring sequence below will make the decimal point light, but you can light any part of the LED display.
Page 85: Electronic Organ
EXPERIMENT #67: ELECTRONIC ORGAN This circuit has a multivibrator connected to a pulse Notes: type oscillator. The multivibrator provides a tremolo effect (a wavering tone), rather than turning the oscillator completely on and off. After you build the project, you can use the control to vary the base current supplied to the NPN transistor.
Page 86: Daylight Early Bird
EXPERIMENT #68: DAYLIGHT EARLY BIRD This is the electronic bird circuit that you built for Notes: Project 1 (Electronic Woodpecker), but now it has a photoelectric control of the transistor base. You know how the CdS cell works. Since this electronic component is activated by daylight, you can use it as an early bird wake up alarm.
Page 87: Intermittent Alarm Detector
EXPERIMENT #69: INTERMITTENT ALARM GENERATOR Now we’ll let one oscillator control another to make Notes: an effective alarm. In this project we have a multivibrator-type oscillator controlling a pulse oscillator. You should recognize the multivibrator circuit on the left side of the schematic. The pulse oscillator’s frequency is in the audible range (20 to 20K Hertz).
Page 88: Basic Operational Amplifier Circuits
VIII. BASIC OPERATIONAL AMPLIFIER CIRCUITS -88-...
Page 89: Comparator
EXPERIMENT #70: COMPARATOR For this section you will need some basic knowledge Notes: about the operational amplifier integrated circuit. First, we can use one power source for both the circuit and the IC, or we can use separate power sources. The operational amplifier can be used as a non- inverting amplifier, an inverting amplifier, or a differential amplifier.
Page 90: Basic Increase In Dc Voltage
EXPERIMENT #71: BASIC INCREASE IN DC VOLTAGE Now we move along to the simplest experiment on If you slide the switch to position A again and press amplifying DC voltage. After you complete the the key to connect 1.5V to the amplifier’s positive (+) wiring, set the switch to position B.
Page 91: Constant-Current Source
EXPERIMENT #72: CONSTANT-CURRENT SOURCE In this project, we will make a constant current Notes: circuit, using an operational amplifier and a transistor. This circuit maintains a constant current even when the source voltage changes, because more energy is used up in the circuit. Look at the schematic.
Page 92: Integrating Circuit
EXPERIMENT #73: INTEGRATING CIRCUIT You know that an LED instantly lights when you turn Notes: it on. But you can also light it up gradually. In this project, you’ll be able to watch the LEDs slowly get brighter while you hold down the key. This circuit is called a Miller integrating circuit.
Page 93: Schmitt Trigger Circuit
EXPERIMENT #74: SCHMITT TRIGGER CIRCUIT We’re going to use the operational amplifier as a Notes: Schmitt trigger circuit and as a comparator. The operational amplifier produces a signal as long as its input voltage exceeds a certain value. Look at the schematic: can you see how it works? It shows that the voltage level that causes the output to turn on is higher then the voltage level that stops the output.
Page 94: Non-Inverting Two Power Supply Amplifier
EXPERIMENT #75: NON-INVERTING TWO-POWER SUPPLY AMPLIFIER In this project, we will make a microphone amplifier, Notes: using the operational amplifier as a non-inverting amplifier with two power sources. The earphone works as a microphone. Start by sliding the switch to position B and completing the wiring for the circuit.
Page 95: Inverting Two Power Supply Amplifier
EXPERIMENT #76: INVERTING TWO-POWER SUPPLY AMPLIFIER Here’s another two-power source microphone Notes: amplifier, but this one is an inverting amplifier. We use the earphone as a microphone again. Slide the switch to position B and assemble the circuit. When you finish the wiring, slide the switch to position A to turn the power on, rotate the control clockwise, and speak into the microphone –...
Page 96: Non-Inverting Single Power Supply Amplifier
EXPERIMENT #77: NON-INVERTING SINGLE-POWER SUPPLY AMPLIFIER In Projects 75 and 76 (“Non-inverting Two-Power Notes: Supply Amplifier,” and “Inverting Two-Power Amplifier,” respectively), we used the operational amplifier with two power sources. In this project, we will make a single-power source, non-inverting microphone amplifier.
Page 97: Two Power Supply Differential Amplifier
EXPERIMENT #78: TWO-POWER SUPPLY DIFFERENTIAL AMPLIFIER This is the last in the series of microphone Here, the speaker is used as a microphone, so the amplifiers. Now we use the operational amplifier as a opposite takes place. When sound makes the coil differential amplifier.
Page 98: Tone Mixing Amplifier
EXPERIMENT #79: TONE MIXING AMPLIFIER How about building a tone mixing amplifier that Notes: mixes two tones together? There are many different kinds of tone mixing circuits, but the operational amplifier is considered one of the best. After completing the wiring, slide the switch to position A to turn on the power.
Page 99: Power Amplifier Using Operational Amplifier
EXPERIMENT #80: POWER AMPLIFIER USING OPERATIONAL AMPLIFIER Now we’re going to produce a loud sound by Notes: combining the operational amplifier with two transistors. After you complete the wiring, set the switch to position A to turn on the power. When you press the key, you hear a loud sound from the speaker.
Page 100: Voltage Controlled Oscillator Circuit
EXPERIMENT #81: VOLTAGE CONTROLLED OSCILLATOR CIRCUIT VCO? What’s that? VCO stands for voltage Notes: controlled oscillator, and as the name implies, this oscillator changes oscillation frequency according to the voltage applied to the circuit. The circuit produces two different output signals that have triangular and square waves.
Page 101: Operational Amplifier Buzzer
EXPERIMENT #82: OPERATIONAL AMPLIFIER BUZZER The dual operational amplifier works well as an Notes: oscillator. In this project, we will build an electric buzzer that makes a continuous beep. You can change the tone of this buzzer by rotating the control.
Page 102: Burglar Alarm
EXPERIMENT #83: BURGLAR ALARM This burglar alarm makes a buzzing sound when Notes: anyone sneaking into your house trips over a wire and breaks it off or disconnects it from a terminal. Instead of stretching out the wire, try to figure out how to connect a switch to the door of your house, so that the alarm sounds when a burglar opens the door.
Page 103: Hand-Operated Sweep Oscillator
EXPERIMENT #84: HAND OPERATED SWEEP OSCILLATOR The electronic buzzer we built in project 82 can only Notes: make a continuous beep, but we can make a similar circuit that produces various siren sounds. Now we’re going to make a siren that gives out a sound with a variable pitch.
Page 104: Falling Bomb Squad
EXPERIMENT #85: FALLING BOMB SOUND Here’s another siren that changes its pitch. The Notes: siren we built in our last project changes pitch from low to high, but this one changes its pitch from high to low and finally stops making any sound. When it stops, press the key and the siren sound will start again.
Page 105: Emergency Siren
EXPERIMENT #86: EMERGENCY SIREN The sirens we built in Projects 84 and 85 (“Hand- Notes: Operated Sweep Oscillator” and “Falling Bomb Sound”, respectively) change pitch only in one direction, but this one makes a low sound that becomes higher, and goes back to its original low sound.
Page 106: First Aid Siren
EXPERIMENT #87: FIRST AID SIREN The sirens we built in Projects 84, 85, and 86 (Hand- Notes: Operated Sweep Oscillator”, “Falling Bomb Sound”, and “Emergency Siren”, respectively) change the pitch of their sounds smoothly between low and high, but this siren is a little different. It gives off alternating high and low sounds.
Page 107: Musical Tempo Generator
EXPERIMENT #88: MUSICAL TEMPO GENERATOR Here’s the operational amplifier version of the Notes: electronic metronome from Project 9 (“Electronic Metronome”). Slide the switch to position B, and connect the wires carefully - this project is much more complicated than most of the others. When you finish assembling the circuit, set the control to the 12 o’clock position and slide the switch to position A to turn on the power.
Page 108: Operational Amplifier Winking Led
EXPERIMENT #89: OPERATIONAL AMPLIFIER WINKING LED Now we’re going to make a winking LED circuit Notes: using a dual operational amplifier. In this circuit, an LED continues to light and turn off slowly. Slide the switch to position B and connect the wires for this circuit.
Page 109: Led Flashing Light
EXPERIMENT #90: LED FLASHING LIGHT The winking LED in the last project stays on and off Notes: for about the same amount of time, but we can make it flash on for a very short time. Start out by sliding the switch to position B and wiring the circuit.
Page 110: Two Led Winker
EXPERIMENT #91: TWO LED WINKER The LED circuits in Projects 89 and 90 (“Operational Notes: Amplifier Winking LED” and “LED Flashing Light”, respectively) each use one LED, but the circuit in this project uses two LEDs that take turns lighting. Slide the switch to position B and assemble the circuit.
Page 111: One Shot Light
EXPERIMENT #92: ONE SHOT LIGHT We’ve built many circuits using the dual operational Notes: amplifier, but there are many other ways to use this handy IC. The one shot multivibrator is one of them. With this multivibrator, we can make the LED stay on for a preset amount of time when the key is pressed - a one shot light.
Page 112: Led Initials
EXPERIMENT #93: LED INITIALS The digital LED display can’t display all 26 letters of Notes: the alphabet, but it’s possible to display many of them. Let’s make an LED display that alternately shows the initials E and P of our ELECTRONIC PLAYGROUND.
Page 113: Wake Up Siren
EXPERIMENT #94: WAKE UP SIREN Are you a late sleeper? Even if you are, don’t worry! Notes: Because you can make this alarm siren that wakes you up gradually as the day dawns. First, set the switch to position B and complete the wiring.
Page 114: Voice Activated Led
EXPERIMENT #95: VOICE ACTIVATED LED You can use a microphone to detect sound. Here we Notes: will make a circuit that lights the LED when the microphone detects sound, using the speaker as a microphone. Slide the switch to position B and assemble the circuit.
Page 115: Logic Tester
EXPERIMENT #96: LOGIC TESTER You know that digital circuits produce high or low (H Notes: or L) outputs (1 or 0). Now we’re going to make a logic tester that shows 1 for high level (H) and 0 for low level (L) on the LED display. Slide the switch to position B and assemble the circuit.
Page 116: More Adventures With Operational Amplifiers
IX. MORE ADVENTURES WITH OPERATIONAL AMPLIFIERS -116-...
Page 117: Alternating Current Sound
EXPERIMENT #97: ALTERNATING CURRENT SOUND The circuit in this project allows you to hear Notes: alternating current. You probably know that the electric power running through your home is an alternating current. All your appliances that receive power from electric outlets operate on AC - including lamps.
Page 118: Light Control Sound Circuit
EXPERIMENT #98: LIGHT CONTROL SOUND CIRCUIT This circuit changes the intervals between each Notes: sound according to the amount of light falling on the CdS cell. The sound changes continuously as you adjust the light intensity. Set the switch to position A to turn on the power after you complete the wiring.
Page 119: Sound Alarm Circuit
EXPERIMENT #99: SOUND ALARM CIRCUIT This alarm gives out an alarm light and sound when Notes: it detects your voice or any other sound. The earphone acts as a microphone. Sounds picked up by the microphone are amplified by IC 1. Diodes Da and Db rectify the amplified signal - that is, they convert the sound signal from AC to DC.
Page 120: Study Timer
EXPERIMENT #100: STUDY TIMER Here’s a timer you can use for taking timed tests or Notes: simply for knowing when an amount of time has passed. You can preset this timer for as much time as you like, up to about 15 minutes. When the time is up, it gives out a continuous buzzer sound until you turn off the power or press the key to reset the circuit.
Page 121: Kitchen Timer
EXPERIMENT #101: KITCHEN TIMER Wouldn’t you like to make a kitchen timer that you Notes: can use for cooking meals? This timer is the same as the test timer in the last project, except for one point. It gives out a buzzer sound for 1 to 2 seconds and automatically stops.
Page 122: Three-Input And Gate Using Operational Amplifier
EXPERIMENT #102: THREE-INPUT “AND” GATE USING OPERATIONAL AMPLIFIER Who says the operational amplifier can’t be used to Notes: make a digital circuit? Here, we use one to make an AND gate. The LED display is the output device. If it displays nothing, at least one of the output signals is logical 0 or low;...
Page 123: Voice Level Meter
EXPERIMENT #103: VOICE LEVEL METER In this project, we will make a voice input level meter. Notes: The brightness of the LED in this circuit changes according to the level of voice input that comes from the microphone (the earphone). Since voice levels change very quickly, the brightness of the LED should also change very quickly.
Page 124: Power-On Reset Circuit
EXPERIMENT #104: POWER-ON RESET CIRCUIT Do you know what a reset circuit does? It activates you use position A to switch to the 9V supply, the other circuits and detects any power fluctuations in 100μF capacitor causes the comparator’s positive order to prevent malfunctions.
Page 125: Delayed Timer
EXPERIMENT #105: DELAYED TIMER This circuit is a delayed timer that uses an Notes: operational amplifier and the CR time constant. You remember that CR stands for capacitor/resistor. A time constant is a circuit that delays an operation. The negative (–) terminal of the operational amplifier receives a voltage of about 4.5V through resistors RA and RB.
Page 126: Pulse Frequency Doubler
EXPERIMENT #106: PULSE FREQUENCY DOUBLER This is a pulse frequency multiplier with one Notes: transistor. It is called a pulse frequency doubler because it doubles the frequency of the input signal. The operational amplifier IC 728 acts as a square- wave oscillator.
Page 127: White Noise Generator
EXPERIMENT #107: WHITE NOISE GENERATOR White noise is a noise that has a wide frequency Notes: range. The shower-like noise you hear when you tune your FM radio to an area with no station is one kind of white noise. It is a useless noise normally, but when you play electronic musical instruments, you can use white noise as a sound source.
Page 128: Dc-Dc Converter With Operational Amplifier
EXPERIMENT #108 DC-DC CONVERTER WITH OPERATIONAL AMPLIFIER Here’s a DC-DC converter circuit; it can gain 5VDC Notes: from 3VDC. Build the project, set the switch to position A, and see how this circuit works. Look at the schematic. IC 1 acts as an oscillator. The output of IC 1 turns on transistor Q1.
Page 129: Communication Circuits
X. COMMUNICATION CIRCUITS -129-...
Page 130: Code Practice Oscillator With Tone Control
EXPERIMENT #109: CODE PRACTICE OSCILLATOR WITH TONE CONTROL Would you like to become an amateur radio ham? Notes: Many radio operators started out using an oscillator with a tone control like this one. The tone control in this project can be very helpful because listening to the same tone for a long time can be very tiring.
Page 131: Crystal Set Radio (Simple-Diode Radio)
EXPERIMENT #110: CRYSTAL SET RADIO (SIMPLE-DIODE RADIO) No project kit is complete without a crystal radio Notes: circuit. Most people in electronics have experimented with this oldest of all radio circuits. Before the days of vacuum tubes or transistors, people used crystal circuit sets to pick up radio signals.
Page 132: Two-Transistor Radio
EXPERIMENT #111: TWO-TRANSISTOR RADIO This is a two-transistor receiver with enough gain Notes: (amplification) to allow you to hear the signal through the speaker. Simple radios like this one require a good antenna and ground system. Connect the circuit and use terminal 74 as the ground terminal.
Page 133: Wireless Code Transmitter
EXPERIMENT #112: WIRELESS CODE TRANSMITTER This project is a simple but effective code transmitter Notes: like the kind used by military and amateur radio operators around the world. When you press and release the key, the transmitter turns on and off in sequence.
Page 134: Am Radio Station
EXPERIMENT #113: AM RADIO STATION If you ever wanted to be a disc jockey, this is your Notes: chance. This AM radio station lets you actually send your voice through the air. You built an AM radio transmitter in the last project, but it could send only a single tone or a series of dots and dashes.
Page 135: Operational Amplifier Radio
EXPERIMENT #114: OPERATIONAL AMPLIFIER RADIO Germanium diode radios generally do not perform Notes: well, but they can be important for emergency communication because they need no power source. Usually, you can listen to a germanium radio only through an earphone, but we have added an operational amplifier to this project so that you can hear it through the speaker.
Page 136: Xi. Testing And Measuring Circuits
XI. TESTING AND MEASURING CIRCUITS -136-...
Page 137: Aural Continuity Tester
EXPERIMENT #115: AURAL CONTINUITY TESTER This circuit emits a sound if the material you are Notes: checking conducts electricity. This is convenient when you are looking at wires, terminals, or other things and cannot look at a signal lamp or LED. Your ears detect the results of the test while your eyes are busy.
Page 138: Conductivity Tester
EXPERIMENT #116: CONDUCTIVITY TESTER You can find the exact value of a resistance if you Notes: use a meter; but when you only want to know approximate resistance values, you can use this conductivity tester. This circuit converts resistance to electric current and compares it with the comparator’s reference current to tell you the approximate range of resistance.
Page 139: Transistor Checker
EXPERIMENT #117: TRANSISTOR CHECKER You will probably test transistors more than any other Notes: component. You can’t tell if a transistor is working or not by looking at it, but this project lets you hear whether or not it is. You can also tell if a transistor is a PNP or an NPN with this circuit.
Page 140: Sinewave Audio Oscillator
EXPERIMENT #118: SINEWAVE AUDIO OSCILLATOR Now, you will learn about generating sinewave Notes: signals. We can define a sinewave as a wave of pure single-frequency tone. For example, a 400Hz sinewave is a wave that oscillates 400 cycles in one second contains other...
Page 141: Low Distortion Sinewave Oscillator
EXPERIMENT #119: LOW DISTORTION SINEWAVE OSCILLATOR In this project, you will build and study a low- Notes: distortion sinewave oscillator. Build this project after you have built and studied the previous project because this one has no transformer; transformers are likely to cause distortion because of their non- linear characteristics.
Page 142: Twin-T Audio Oscillator
EXPERIMENT #120 TWIN-T AUDIO OSCILLATOR Because it is very stable, the twin-T type audio Notes: oscillator is very popular for use with electronic organs and electronic test equipment. The oscillation frequency depends on the resistors and capacitors in the twin-T network. The letter T is used because the schematic diagram for this circuit shows its resistors and capacitor arranged in the shape of the letter T.
Page 143: Pulse Oscillator Tone Generator
EXPERIMENT #121: PULSE OSCILLATOR TONE GENERATOR This project is a pulse-tone oscillator with an Notes: adjustable frequency that can obtain a wide range of notes. With practice, you can play tunes on it that sound like an electronic organ. To play a tune, adjust the control to the proper note and press the key.
Page 144: Audio Signal Tracer
EXPERIMENT #122: AUDIO SIGNAL TRACER This project is a simple transistor audio amplifier Notes: used as an audio signal tracer. You can use this amplifier to troubleshoot transistor audio equipment. When a circuit does not work correctly, you can connect the wires to different terminals in the circuit until you find the stage or component that does not pass the signal along.
Page 145: Radio Frequency Signal Tracer
EXPERIMENT #123: RADIO FREQUENCY SIGNAL TRACER This project is a wide band, untuned RF signal Notes: tracer. You can use it to find sources of RF noise and interference, and to check for antenna signals. This circuit is like an untuned crystal set. We use the 100pF capacitor for the input in this circuit because it blocks DC and the 60Hz power line frequency so that the wires can touch almost...
Page 146: Square Wave Audio Oscillator
EXPERIMENT #124: SQUARE WAVE AUDIO OSCILLATOR You can use square waves as test signals, too. Notes: Square waves are produced by multivibrator oscillators. Remember, you used this type of circuit in previous projects. The name square wave comes from the pattern produced by the signal on an oscilloscope (shown below).
Page 147: Sawtooth Wave Oscillator
EXPERIMENT #125: SAWTOOTH WAVE OSCILLATOR When you connect the signal from this oscillator to Notes: an oscilloscope, it makes a pattern that looks like the teeth of a saw (as shown below). The shape of this wave comes from the slow charging of the 0.1μF capacitor through the control and the 100kΩ...
Page 148: Rain Detector
EXPERIMENT #126: RAIN DETECTOR This circuit works as a rain detector. When the Notes: resistance between the long wires is more than about 250kΩ, no current is drawn from the circuit - whether the key is open or closed. When the key is closed and water (or anything else that has a resistance of less than about 400kΩ) is connected to both of the test wires, the speaker produces a tone.
Page 149: Water Level Buzzer With Operational Amplifier
EXPERIMENT #127: WATER LEVEL BUZZER WITH OPERATIONAL AMPLIFIER You can use the dual operational amplifier as a Notes: comparator for detecting changes in voltage. In this project, we’re going to use this comparator function to make a water buzzer that sounds when the wire ends come into contact with water.
Page 150: Metal Detector
EXPERIMENT #128: METAL DETECTOR This project demonstrates how a metal detector Notes: works. When the coil comes close to the metal, the oscillator changes the frequency; then, you know there is something close by that is made of metal. This type of metal detector has been used to locate lost treasures, buried pipes, hidden land mines, and so on.
Page 151: Water Level Alarm
EXPERIMENT #129: WATER LEVEL ALARM This electronic circuit is a radio transmitter/alarm When the transistor is on, the RF oscillator device used to monitor rising water levels such as produces an RF signal. These probes can be made on rivers, dams, and spillways. Its alarm signals are of almost any insulated conductor, but large surface received by a standard AM radio.
Page 152: Three-Step Water Level Indicator
EXPERIMENT #130: THREE-STEP WATER LEVEL INDICATOR This project uses the LED and an audio oscillator Notes: alarm to indicate three different levels of water in a container. The water is used as a conductor to complete the circuits and show the water level. When the water is below all three of the wire connections, only the bottom segment (D) of the LED is on (indicating a low water level).
Page 153: Index
INDEX We’ve added this listing to aid you in finding Do you want to learn more about a specific type of experiments and circuits that you might be circuit? Use this Index to look up all the other uses especially interested in. Many of the experiments are and applications of any specific circuit - then turn to listed two, three, or four times - since they can be those and read what we’ve told you in each one.
Page 154 LOGIC AND COMPUTER CIRCUITS AND Gate: 27, 36, 40, 41 Data: DTL: 27, 28, 29, 30, 35 Exclusive OR: 30, 38 Flip-flop: 32, 33, 44, 45, 55, 56 Inverting: 70, 75, 76, 77, 80, 95, Line: NAND Gate: 29, 43 NOR Gate: OR Gate: 37, 38, 39, 42...
Page 155: Parts List
PARTS LIST PCB for BA728 Bar Antenna with Holder Resistors Battery Box Plastic (2) Capacitors 100Ω 5% 1/4W (4) 10pF, ceramic disc type 470Ω 5% 1/4W 100pF, ceramic disc type 1kΩ 5% 1/4W 0.001μF, ceramic disc type 2.2kΩ 5% 1/4W 0.01μF, ceramic disc type 4.7kΩ...
Page 156: Definition Of Terms
DEFINITION OF TERMS Common abbreviation Carbon A chemical element used to alternating current. make resistors. Clockwise In the direction in which the Alternating Current A current that is constantly hands of a clock rotate. changing. Coil When something is wound in a Amplitude modulation.
Page 157 Electric Field The region of electric attraction Inductance The ability of a wire to create or repulsion around a constant an induced voltage when the voltage. This usually current varies, due to magnetic associated with the dielectric in effects. a capacitor. Inductor A component that opposes Electricity...
Page 158 Ohm’s Law relationship between Semiconductor A material that has more voltage, current, resistance than conductors but resistance. less than insulators. It is used to construct diodes, transistors, Ohm, (Ω) unit measure and integrated circuits. resistance. Series When electrical components Oscillator A circuit that uses feedback to are connected one after the generate an AC output.
Page 159: Identifying Resistor Values
IDENTIFYING RESISTOR VALUES Use the following information as a guide in properly identifying the value of resistors. BAND 1 BAND 2 Multiplier Resistance 1st Digit 2nd Digit Tolerance Color Digit Color Digit Color Multiplier Color Tolerance BANDS Black Black Black Silver ±10% Multiplier...
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