Question

The emitter of a transistor is _______ doped.

• A. Lightly
• B. Heavily
• C. Moderately
• D. Non

Hint:

In BJTs, the emitter is always the most heavily doped region to ensure maximum injection of charge carriers.

Answer 1

The Correct Option is B

Step 1: Purpose of the emitter
The emitter injects charge carriers (electrons or holes) into the base region. 
Step 2: Doping rationale
To ensure a high injection efficiency, the emitter is heavily doped so that it can provide a large number of charge carriers. 
Step 3: Comparison
Base is lightly doped, collector is moderately doped. The doping gradient supports unidirectional carrier flow. 
Conclusion: The emitter is heavily doped to efficiently inject carriers into the base.