Question

for operation as an amplifier, the base of an npn transistor must be
select one:
o a. positive with respect to the collector
o b. negative with respect to the emitter
o c 0 v
o d. positive with respect to the emitter

Explanation:

To operate an NPN transistor as an amplifier, the base - emitter junction must be forward - biased. In a forward - biased base - emitter junction of an NPN transistor, the base is at a higher (positive) potential with respect to the emitter.

• Option a: The base should be positive with respect to the emitter, not the collector. For an NPN transistor in active (amplifier) mode, the collector is at a higher potential than the base. So this option is incorrect.
• Option b: If the base is negative with respect to the emitter, the base - emitter junction is reverse - biased, and the transistor will not operate as an amplifier. So this option is incorrect.
• Option c: A base at 0 V with respect to the emitter means the base - emitter junction is not forward - biased, so the transistor will not conduct properly for amplification. So this option is incorrect.
• Option d: This option satisfies the condition for forward - biasing the base - emitter junction of an NPN transistor, which is required for amplifier operation.

Answer:

d. positive with respect to the emitter