Biasing an active device, such as a bipolar junction transistor (BJT), requires that you set the dc voltages and currents of the device. To optimize the desired result, you need various bias values.
If you open up the perennial favourite electronics textbook The Art Of Electronics and turn to the section on transistors, you will see a little cartoon. A transistor is shown as a room in which ...
The use of transistors for switching things ON and OFF is a key feature of proper hacking. The ability for bipolar transistors to turn things ON and OFF is one of the less known uses while transistors ...