How a Transistor Works EASY! - Electronics Basics 22 (Updated)

hello once again and welcome to episode 22 of simply electronics basics today we're going to have a look at the transistor what a transistor is and how it works in a simple circuit so to start off with transistors are semiconductor devices this means that transistors can be both conductive allowing current to pass through them or non conductive which blocks current from flowing through it transistors can be used as a switch essentially emulating a mechanical switch but in a solid state form before I move on I have a transistor connected within this circuit it's a simple circuit consisting of an approximately three volt power supply connected to an LED with the collector and emitter of this transistor connected in series currently we have everything connected and we are playing this circuit live what we would expect is current to flow from this power supply through the LED back through the transistor and to the power supply and in that case the LED should be late but the LED isn't lit because no current is flowing through the circuit so why is this well that's because by default transistors are in their non conductive state and something needs to change here to turn this transistor on enabling it's conductive state to turn the transistor on to its conductive state we need to apply a voltage to the base of the transistor in this case we have the collector and the emitter but we also have a third terminal which is the base so moving on to my second circuit I have exactly the same circuit except now I have a separate power supply which supplies positive voltage to the base of this transistor because a voltage is now applied to the base of this transistor this has turned this transistor into its conductive state because this transistor is now in its conductive state current from our first power supply is now able to flow from the power supply through the led through the transistor and back this power supply I have a switch connected to the second power supply which supplies voltage to the base of the transistor if I turn this power supply off by disconnecting it you can see the circuit below it stops as well because now the transistor is back to its non conductive state because voltage is not being applied to the base of the transistor so why are transistors so common and so useful well without transistors today we simply wouldn't have the luxury of computers and other digital devices transistors can act like very fast switches that we can control to switch on and off at very fast speeds we can switch them on and off at a rate of millions of times a second in fact if you think of a computer you most likely know that they work with binary data essentially zeros and ones those zeros and ones essentially represent the on and off state of a transistor and there are billions of transistors in your computer's processor this means that the computer can understand those transistor switches as zeros and ones and encode them into useable data and instructions because transistors can turn on and off so quickly this gives us many advantages when we want to control other devices such as LED lights motors enabling us to turn them on or off vary the speeds vary the brightness frequency etc the other advantage to transistors is that we can use small logic level voltages to turn the transistor on and off and the control higher powered devices I'm supplying the base of this transistor with only a 3.3 volt logic level voltage but the transistor is able to switch on and off this 12 volt high-powered led and in fact we can use bigger transistors to switch even bigger loads such as motors and other higher powered devices so I have this transistor supplied with a low voltage switching on and off a higher powered load I'm using a digitally controlled voltage source here which is pulsing voltage to the base of the transistor every 10 microseconds obviously it's much slower in every circuit mainly for your understanding but also because every circuit cannot show in real time the pulsing of voltage here to the base of this transistor is switching the circuit below on and off the pulsing is known as pulse width modulation so this voltage source could be a digital device like a microcontroller or a computer I won't go too deep into pulse width modulation this is for a later video but the amazing fact here is that I am able to digitally control a high-powered device with a low powered voltage source to the base of the transistor so obviously depending on the type and size of a transistor they are able to switch high powered and low powered devices we've seen or talked about an example of both here make sure you subscribe and follow along with simply electronics as we dive deeper into more uses of transistors building simple circuits and where you can learn about many other components just check out the simple electronics basics playlist before you leave there is a link in the description that you can click to interact with this live circuit yourself make sure you leave a like on this video if you enjoyed it and leave your comments below and subscribe for more you

Channel: Simply Electronics

Views: 635,200

Keywords: electronics, basics, current, electric, electron, flow, tutorial, how, to, energy, hobby, power, circuit, volts, amps, watts, simple, simply, making, bigclive, big, clive, bigclivedotcom, diy, hack, roman, ursu, arduino, pi, raspberry, linux, automation, android, servo, motor, transistor, how does a transistor work, what is a transistor, what are transistors, transistor circuits, how to use a transistor, transistor basics

Id: HqhE-8xXeCQ

Length: 5min 42sec (342 seconds)

Published: Sun Sep 18 2016