The below Fig. shows the common emitter npn amplifier circuit. Note that a battery VBB is connected in the input circuit in addition to the signal voltage. This d.c. voltage is known as bias voltage and its magnitude is such that it always keeps the emitter-base junction forward *biased regardless of the polarity of the signal source. Operation. During the positive half-cycle of the signal, the forward bias across the emitter-base junction is increased. Therefore, more electrons flow from...
