1. TRANSISTOR BASICS 1 TRANSISTOR BASICS Lakeland Regional High School October 20, 2015

2. TRANSISTOR BASICS2 WHAT CAN IT DO? Although transistors have many applications for now we will be concerned with only a couple of them

3. TRANSISTOR BASICS3 MANY TYPES OF TRANSISTORS For this presentation we will focus on the Bipolar transistor. They can be either an NPN or a PNP depending on the way they are manufactured

4. TRANSISTOR BASICS4 NPN AND PNP The NPN type have an arrow at the emitter pointing out This is in contrast to the PNP type that has an emitter arrow pointing in

5. TRANSISTOR BASICS5 Bipolar Transistors NPN PNP

6. TRANSISTOR BASICS6 What do we get out of them?  For every 1 ma of current to the base of the transistor, we usually get 10 to 100 times more thru the collector and this feature is very useful  In the electronics world this translates to a small signal in to get a big signal out

7. TRANSISTOR BASICS7 WHERE DOES THIS ENERGY COME FROM? Even though we git a big signal out we do not get something for nothing Bipolar transistors also require connection to a DC source- this is where the energy comes from This does not make them any less useful

8. TRANSISTOR BASICS8 What will we do with them? For our lab experiment we will set up a simple circuit that controls how much voltage appears at the base of the transistor. For our lab experiment we will set up a simple circuit that controls how much voltage appears at the base of the transistor. We will do this by varying the resistance and thus the voltage We will do this by varying the resistance and thus the voltage This will control the current to the base which will control the voltage thru the collector This will control the current to the base which will control the voltage thru the collector

9. TRANSISTOR BASICS9 What will we do with them? When we have appreciable collector current we say that the transistor is “on” When we have appreciable collector current we say that the transistor is “on” We will measure the base current, base voltage and the collector current We will measure the base current, base voltage and the collector current

10. TRANSISTOR BASICS10 What will we do with them? This will tell us a lot about what is going on and demonstrate how the transistor is useful This will tell us a lot about what is going on and demonstrate how the transistor is useful Eventually the transistor will go into “saturation” and we will see that the collector current levels off (or stops increasing) Eventually the transistor will go into “saturation” and we will see that the collector current levels off (or stops increasing)

11. TRANSISTOR BASICS11 Resistance from base to groundBase Current IbCollector Current Ic