Question

The bipolar junction transistor is used as a switch ‘ON’ in

• A. Active region
• B. Cut off region
• C. Saturation region
• D. Both $\left(B\right)$ and $\left(C\right)$

Answer 1

The correct option is C Saturation region

Transistor acts as switch ON in saturation region. In this mode or region the highest base current is applied, leading to the overall collector current causing the average collector-emitter voltage to fall and the leakage surface as small as possible and the maximum current that flows across this transistor.