Question

A transistor has 3 impurity regions of different doping levels. In the order of increasing doping level, the regions are

• A. emitter, base, collector
• B. collector, base, emitter
• C. base, emitter, collector
• D. base, collector, emitter

Hint:

Remember: In a transistor, the emitter is most heavily doped, followed by the collector, and the base is the least doped and thinnest.

Answer 1

The Correct Option is D

Step 1: Understand the doping levels in a transistor.
In a transistor, the three regions have different doping levels: Base: Very lightly doped and thin. 
Collector: Moderately doped. 
Emitter: Heavily doped to inject a large number of charge carriers. 
Step 2: Arrange in increasing doping order.
\[ \text{Base (least doped)} < \text{Collector (moderately doped)} < \text{Emitter (heavily doped)} \] Step 3: Select the correct option.
The correct order is: base, collector, emitter \( \Rightarrow \) option (4).