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 ...

Just as the common emitter amplifier and common base amplifier each tied those respective transistor terminals to a fixed potential and used the other two terminals as amplifier input and output, so ...

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.