Transistor Circuits_1-100.pdf

save on your computer as.pdf:1-100 Transistor circuits.pdf Go to:101-200 Transistor Circuits Go to:100 IC Circuits See TALKING ELECTRONICS WEBSITE email Colin Mitchell:.au INTRODUCTIONThis e-book contains 100 transistor circuits.The second part of this e-book will contain a further100 circuits.Most of them can be made with components from your junk box and hopefully you can put them together in less than an hour.The idea of this book is to get you into the fun of putting things together and theres nothing more rewarding than seeing something work.Its amazing what you can do with a few transistors and some additional components.And this is the place to start.Most of the circuits are stand-alone and produce a result with as little as 5 parts.We have even provided a simple way to produce your own speaker transformer by winding turns on a piece of ferrite rod.Many components can be obtained from transistor radios,toys and other pieces of discarded equipment you will find all over the place.To save space we have not provided lengthy explanations of how the circuits work.This has already been covered in TALKING ELECTRONICS Basic Electronics Course,and can be obtained ona CD for$10.00(posted to anywhere in the world)See Talking Electronics website for more details:http:/Transistor data is at the bottom of this page and a transistor tester circuit is also provided.There are lots of categories and I am sure many of the circuits will be new to you,because some of them have been designed recently by me.Basically there are two types of transistor:PNP and NPN.We have labelled the NPN transistor as BC547.This means you can use ANY NPN transistor,such as 2N2222,BC108,2N3704,BC337 and hundreds of others.Some circuits use TUN for Transistor Universal NPN and this is the same as our reasoning-the transistor-type is just to let you know it is not critical.BC557 can be replaced by:2N3906,BC327 and many others.Dont worry too much about the transistor-type.Just make sure it is NPN,it this is the type needed.If it is an unknown transistor-type,you need to identify the leads then put it in the circuit.You have a choice of building a circuit in the air,or using an experimenter board(solderless breadboard)or a matrix board or even a homemade printed circuit board.The choice is up to you but the idea is to keep the cost to a minimum-so dont buy anything expensive.If you take parts from old equipment it will be best to solder them together in the air(as they will not be suitable for placing on a solderless breadboard as the leads will be bent and very short).This way they can be re-used again and again.No matter what you do,I know you will be keen to hear some of the noisy circuits in operation.Before you start,the home-made Speaker Transformer project and Transistor Tester are the first things you should look at.If you are starting in electronics,see the Worlds Simplest Circuit.It shows how a transistor works and three transistors in the 8 Million Gain project will detect microscopic levels of static electricity!You can look through the Index but the names of the projects dont give you a full description of what they do.You need to look at the circuits.And I am sure you will.KIT OF PARTSTalking Electronics supplies a kit of parts that can be used to build the majority of the circuits in this book.The kit costs$15.00 plus postage.Kit for Transistor Circuits-$15.00A kit of components to make many of the circuits presented in this eBook is available for$15.00 plus$7.00 post.Or email Colin Mitchell:.auThe kit contains the following components:(plus extra 30 resistors and 10 capacitors forexperimenting),plus:3-47R5-220R5-470R5-1k5-4k75-10k 2-33k 4-100k4-1M1-10k mini pot1-100k mini pot2-10n 2-100n5-10u electrolytics5-100u electrolytics5-1N4148 signal diodes6-BC547 transistors-NPN-100mA2-BC557 transistors -PNP-100mA1-BC338 transistor -NPN-800mA3-BD679 Darlington transistors-NPN-4amp5-red LEDs5-green LEDs5-orange LEDs2-super-bright WHITE LEDs-20,000mcd1-3mm or 5mm flashing LED1-mini 8R speaker1-mini piezo 1-LDR(Light Dependent Resistor)1-electret microphone1m-0.25mm wire 1m-0.5mm wire 1-10mH inductor1-push button 5-tactile push buttons1-Experimenter Board(will take 8,14 and 16 pin chips)5-mini Matrix Boards:7 x 11 hole,11 x 15 hole,6 x 40 hole,surface-mount 6 x 40 hole board or others.Photo of kit of components.Each batch is slightly different:There are more components than you think.plus an extra bag of approx 30 components.The 8 little components are switches and the LDR and flashing LED is hiding.In many cases,a resistor or capacitor not in the kit,can be created by putting two resistors or capacitors in series or parallel or the next higheror lower value can be used.Dont think transistor technology is obsolete.Many complex circuits have one or more transistors to act as buffers,amplifiers or to connect one block to another.It is absolutely essential to understand this area of electronics if you want to carry out design-work or build a simple circuit to carry out a task.We also have an eBook:THE TRANSISTOR AMPLIFIER with over 100 different transistor circuits.proving the transistor can be connected in so many ways.THEORY Read the full article HERE(the Transistor Amplifier eBook)The first thing you will want to know is:HOW DOES A TRANSISTOR WORK?Diagram A shows an NPN transistor with the legs covering the symbol showing the name for each lead.The transistor is a general purpose type and and is the smallest and cheapest type you can get.The number on the transistor will change according to the country where the circuit was designed but the types we refer to are all the SAME.Diagram B shows two different general purpose transistors and the different pinouts.You need to refer to data sheets or test the transistor to find the correct pinout.Diagram C shows the equivalent of a transistor as a water valve.As more current(water)entersthe base,more water flows from the collector to the emitter.Diagram D shows the transistor connected to the power rails.The collector connects to a resistor called a LOAD and the emitter connects to the 0v rail or earth or ground.Diagram E shows the transistor in SELF BIAS mode.This is called a COMMON EMITTER stage and the resistance of the BASE BIAS RESISTOR is selected so the voltage on the collector is half-rail voltage.In this case it is 2.5v.To keep the theory simple,heres how you do it.Use 22k as the load resistance.Select the base bias resistor until the measured voltage on the collector 2.5v.The base bias will be about 2M2.This is how the transistor reacts to the base bias resistor:The base bias resistor feeds a small current into the base and this makes the transistor turn on and create a current-flow though the collector-emitter leads.This causes the same current to flow through the load resistor and a voltage-drop is created across this resistor.This lowers the voltage on the collector.The lower voltage causes a lower current to flow into the base and the transistor stops turning on a slight amount.The transistor very quickly settles down to allowing a certain current to flow through the collector-emitter and produce a voltage at the collector that is just sufficient to allow the right amount of current to enter the base.Diagram F shows the transistor being turned on via a finger.Press hard on the two wires and the LED will illuminate brighter.As you press harder,the resistance of your finger decreases.This allows more current to flow into the base and the transistor turns on harder.Diagram G shows a second transistor to amplify the effect of your finger and the LED illuminates about 100 times brighter.Diagram H shows the effect of putting a capacitor on the base lead.The capacitor must be uncharged and when you apply pressure,the LED will flash brightly then go off.This is because the capacitor gets charged when you touch the wires.As soon as it is charged NO MORE CURRENT flows though it.The first transistor stops receiving current and the circuit does not keepthe LED illuminated.To get the circuit to work again,the capacitor must be discharged.This is a simple concept of how a capacitor works.A large-value capacitor will keep the LED illuminated for a longer period of time.Diagram I shows the effect of putting a capacitor on the output.It must be uncharged for this effect to work.We know from Diagram G that the circuit will stay on when the wires are touched but when a capacitor is placed in the output,it gets charged when the circuit turns ON and only allows the LED to flash.1.This is a simple explanation of how a transistor works.It amplifies the current going into the base about 100 times and the higher current flowing through the collector-emitter leads will illuminate a LED.2.A capacitor allows current to flow through it until it gets charged.It must be discharged to see the effect again.Read the full article HEREINCREASING THE VOLTAGEYou can change the voltage of many circuits from 6v to12v or 3v to 6v without altering any of the values.I can see instantly if this is possible due to the value of the components and heres how I do it:Look at the value of the resistors driving the load(s).Work out the current entering each load and see if it is less than the maximum allowable.Then,take a current reading on the lower voltage.Increase the voltage to the higher value and take another reading.In most cases the current will increase to double the value(or a little higher than twice the original value).If it is over 250%higher,you need to feel each of the components and see if any are getting excessively hot.If any LEDs are taking excessive current,double the value of the current-limiting resistor.If any transistor is getting hot,increase the value of theload resistor.In most cases,when the voltage is doubled,the currentwill will crease to double the original.This means the circuit will consume 4 times the original energy.This is just a broad suggestion to answer the hundredsof emails I get on this topic.CONTENTS circuits in red are in 101-200 CircuitsNote:All circuits use 1/4 watt resistors unless specified on the diagram.Adjustable High Current Power SupplyAerial AmplifierAlarm Using 4 buttonsAmazing LED Flasher-for BikesAmmeter 0-1A Amplifier uses speaker as microphoneAM Radio-5 TransistorAmplifying a Digital SignalArc Welder Simulator for Model RailwaysAudio Amplifier(mini)Automatic Battery ChargerAutomatic Bathroom LightAutomatic Garden LightAutomatic Light-see also Night LightAutomatic PIR LED LightAutomatic Solar LightBattery CapacityBattery Charger -12v AutomaticBattery Charger MkII-12v trickle chargerBattery-Low BeeperBattery Monitor MkIBattery Monitor MkIIBench Power SupplyBike Flasher Bike Flasher-amazing Bike Turning SignalBeacon(Warning Beacon 12v)Beeper BugBlocking OscillatorBlown Fuse IndicatorBook LightBoom Gate LightsBootstrap AmplifierBoxesBreakdown BeaconBright Flash from Flat Battery Buck Converter for LEDs 48mABuck Converter for LEDs 170mABuck Converter for LEDs 210mABuck Converter for LEDs 250mABuck Converter for 3watt LEDBuck Regulator 12v to 5vMicrophone Pre-amplifierMobile P hone Alert-2 Model Railway Point Motor DriverModel Railway timeMotor Speed ControllerMotor Speed Control(simple)Movement DetectorMultimeter-Voltage of Bench SupplyMusic On Hold Music to ColourNail FinderNiCd ChargerNight Light-see also Automatic LightOn-Off via push ButtonsOP-AMP-using 3 transistorsPassage PIR LED LightPhaser Gun Phase-Shift Oscillator-good designPhone Alert Phone Alert-2(for mobile phone)Phone Bug Phone Tape-1Phone Tape-2Phone Tape-3Phone Tape-4 -using FETsPhone Transmitter-1Phone Transmitter-2Phone Transmitter-3Phone Transmitter-4Phase-shift OscillatorPlant Needs WateringPIC Programmer Circuits 1,2 3Piezo Buzzer-how it works PIR DetectorPIR LED LightPoint Motor DriverPowering a LEDPower ONPower Supplies-FixedPower Supplies-Adjustable LMxx seriesPower Supplies-Adjustable 78xx seriesPower Supplies-Adjustable from 0v Power Supply-Inductively CoupledCable TracerCamera ActivatorCapacitor Discharge Unit MkII(CDU2)TrainsCapacitor TesterCar Detector(loop Detector)Car Light Extender MkIICar Light AlertCFL Driver(Compact Fluorescent)5wCharge-current without a multimeterChaser 3 LED 5 LED Chaser using FETsCharger-NiCdCharging Battery via Solar PanelChip Programmer(PIC)Circuits 1,2 3 Circuit Symbols Complete list of SymbolsClock-Make Time FlyClap Switch-see also VOXClap Switch -turns LED on for 15 secondsCode LockCode PadCoin Counter Colour Code for Resistors-all resistorsColpitts OscillatorCombo-2-Transistor testerConstant CurrentConstant Current Drives two 3-watt LEDsConstant Current for 12v carConstant Current Source Cct 2 Cct 4Constant Current 1.5ampContinuity TesterCourtesy Light Extender for Cars MkIICrossing LightsCrystal Tester Dancing FlowerDancing Flower with Speed ControlDark Detector for ProjectDark Detector with beep AlarmDarlington TransistorDecaying FlasherDelay Before LED turns ONDelay Turn-off-turns off circuit after Power ZenerProject can turn ON when DARKPush-On Push OFFPWM ControllerQuiz TimerRadio-AM-5 TransistorRailway timeRandom Blinking LEDsRechargeable Battery CapacityRectifying a VoltageRelay ChatterRelay OFF DelayRelay ProtectionResistor Colour CodeResistor Colour Code-4,5 and 6 BandsReversing a MotorRobo RollerRobotRobot Man-Multivibrator Safe 240v SupplySchmitt TriggerSCR with TransistorsSecond Simplest CircuitSequencerShake Tic Tac LED TorchSignal by-passSignal InjectorSimple FlasherSimple Logic ProbeSimple Touch-ON Touch-OFF SwitchSimplest Transistor TesterSirenSiren Soft Start power supplySolar EngineSolar Engine Type-3Solar Light-AutomaticSolar Panel-charging a battery Solar PhotovoreSound to LightSound Triggered LEDSpeaker TransformerSpeed Control-MotorSpy AmplifierStrength TesterdelayDivide-by CircuitDoor-Knob AlarmDriving a LEDDrive 20 LEDsDynamic Microphone AmplifierDynamo Voltage Doubler Electronic DrumsElectronic FilterEmergency LightFading LEDFerret FinderFET ChaserField Strength Meter for 27MHzFlasher(simple)Flashing 2 LEDsFlash from Flat BatteryFlashing Beacon(12v Warning Beacon)Flashing LED-See Flasher Circuits on web see:3 more in:1-100 circuits see Bright Flash from Flat Battery see Flashing 2 LEDs see LED Driver 1.5v White LED see LED Flasher see LED Flasher 1-Transistor see LEDs Flash for 5 secs see White LED Flasher see Dual 3v White LED Flasher see Dual 1v5 White LED Flasher see 1.5v LED Driver see 1.5v LEDFlasher see 3v White LED flasherFlashing tail-light(indicator)Fluorescent Inverter for 12v supplyFM Transmitters-11 circuitsFog HornFRED PhotopopperFridge Alarm Fuse InidicatorGold DetectorSun Eater-1Sun Eater-1ASuper EarSuper-Alpha Pair(Darlington Transistor)Supply Voltage MonitorSwitch DebouncerSziklai transistorTelephone amplifierTelephone Bug see also Transmitter-1 -2Telephone Taping-see Phone Tape Testing A TransistorTicking BombTime Delay CircuitsToggle a Push Button using 2 relaysToggle A RelayToroid-using a toroid InductorTouch SwitchTouch-ON Touch-O