Question

A transistor is used in the common emitter mode as an amplifier then:
(A) the base emitter junction is forward baised.
(B) the base emitter junction is reverse baised.
(C) the input signal is connected in series with the voltage applied to bias the base emitter junction.
(D) the input signal is connected in series with the voltage applied to bias the base collector junction.

• A. $A,B$
• B. $A,D$
• C. $A,C$
• D. Only $C$

Answer 1

The correct option is C $A,C$

In a common-emitter transistor, the base part is used as the input junction, and the emitter part is used as the output junction.

Hence, the base-emitter junction is forward biased.

Now, for a CE transistor’s proper functioning as the amplifier, the collector-base junction should be in reverse bias. The input signal is connected in series with the voltage applied to bias the base-emitter junction so that a majority of the carrier charges can be used in the circuit.

Therefore, option (C) is correct.