Two reasons
- Signals - to transmit information
- Loads - to turn on and off power (to devises)

- Vacuum Tube Triode

- Semiconductor (types)


- Bi Polar Advantages
- Can be designed to control Large Currents
- Small
- Bi Polar Disadvantages
- current controlled
- Heat given off
- direct current only
- bias resistor needed
Create a BiPolar Trasistor simulation on TINA


Create a MOSFET transistor circuit simulation on TINA

©Geoff McCulloch, 2003