THE TRANSISTOR AS A SWITCH
CLICK HERE TO BUY THE CD

With the switch open, no base current flows, therefore no collector current can flow. The transistor is said to be CUT OFF.

With the switch closed, base current flows causing collector current to flow. The battery voltage is dropped across the lamp causing the collector voltage to fall to a very low value.
The transistor is said to be SATURATED.


Copyright Graham Knott 1999