Working of a PNP Transistor
A PNP transistor is like two PN junction diodes, which are placed back-to-back. At each junction, there is a depletion region which gives rise to a potential barrier. The external biasing of the junction is provided by the batteries VEE and VCC as shown in animation. The emitter base junction is forward biased and the collector base
junction is reverse biased. Since the emitter-base junction is forward biased, a large
number of holes cross the junction and enters the base. At the same time, very few electrons flow from the base to the emitter. These electrons, when they reach emitter, recombine with an equal number of holes in the emitter. The loss of total number of holes in the emitter is made by flow of an equal number of electrons from the emitter to the positive terminal of the battery. The flow of holes from the emitter to base gives rise to emitter current IE. In the emitter, IE is due to the flow of holes. But in the external circuit the current is due to the flow of...