What is the significance of depletion region being wide or small in a transistor as a switch?

Asked by divyakhare | 14th Feb, 2012, 09:49: AM

Expert Answer:

1. Cut-off Region In this region, the operating conditions of the transistor are zero input base current ( IB ), zero output collector current ( IC ) and maximum collector voltage ( VCE ) which results in a large depletion layer and no current flowing through the device. Therefore the transistor is switched "Fully-OFF". 2. Saturation Region In this region, the transistor will be biased so that the maximum amount of base current is applied, resulting in maximum collector current resulting in the minimum collector emitter voltage drop which results in the depletion layer being as small as possible and maximum current flowing through the transistor. Therefore the transistor is switched "Fully-ON".

Answered by  | 14th Feb, 2012, 10:19: AM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.