The above figure shows the circuit symbol of a transistor. Select the correct statements given below:
(A) The

Question

The above figure shows the circuit symbol of a transistor. Select the correct statements given below:
(A) The transistor has two segments of p-type semiconductor separated by a segment of n-type semiconductor.
(B) The emitter is of moderate size and heavily doped.
(C) The central segment is thin and lightly doped.
(D) The emitter base junction is reverse biased in common emitter amplifier circuit.

Accepted Answer

In any bipolar junction transistor (BJT): 
1. The central segment (base) is always very thin and lightly doped to minimise the recombination of charge carriers (Statement C is correct). 
2. The emitter is heavily doped to supply a large number of majority charge carriers and is of moderate size, while the collector is of the largest size to dissipate heat (Statement B is correct).
3. In a common-emitter amplifier circuit, the emitter-base junction is always forward-biased (making Statement D incorrect). 
Since Statement D is incorrect, any option containing (D) is wrong. Thus, the correct combination is (B) and (C). (Statement A specifically describes a p-n-p transistor, which may not be universally true if the missing figure depicted an n-p-n transistor).

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