question_answer

When n-p-n transistor is used as an amplifier

A)  electrons move from emitter to base

B)  electrons move from base to emitter

C)  electrons move from collector to base

D)  holes move from base to emitter

Correct Answer: A

Solution :

Key Idea: Holes move opposite to direction of electrons.                 When, n-p-n transistor is used as a common base amplifier, the emitter-base input circuit is forward biased and collector-base output circuit is reverse biased. when \[{{i}_{E}},\,{{i}_{B}},\,{{i}_{C}}\] are emitter, base arid collector current. The arrow from base to emitter represents the direction of hole current that is the conventional current which is opposite to direction of electron current. Thus, electrons move from emitter to base.