Need for biasing the transistor

For normal operation, base-emitter junction should be forward biased and the collector-base junction reverse biased. The amount of bias required is significant for the establishment of the operating or the Q-point which is dictated by the mode of operation desired.

In case the transistor is not biased properly, it would :

  • work inefficiently
  • produce distortion in the output signal
  • with the change in transistor parameters or temperature rise, the operating point may shift and the amplifier output will be unstable.