Question

In a p-n-p transistor,

• A. emitter is heavily doped and collector is moderately doped.
• B. emitter is moderately doped and collector is heavily doped.
• C. both emitter and collector are heavily doped.
• D. both emitter and collector are moderately doped.

Hint:

Remember that the doping levels in a transistor are crucial for controlling its current gain and behavior.

Answer 1

The Correct Option is A

In a p-n-p transistor, the emitter is heavily doped to increase the number of charge carriers for current conduction. The collector is moderately doped to allow proper control over the current flow. The base, which is located between the emitter and collector, is lightly doped. Thus, the correct relation for the doping levels in a p-n-p transistor is: \[ \text{Emitter is heavily doped, Collector is moderately doped.} \]

Answer 2

Step 1: Understand the structure of a p-n-p transistor.
A p-n-p transistor consists of two p-type semiconductor regions separated by a thin n-type region. The three regions are:
- Emitter (p-type)
- Base (n-type)
- Collector (p-type)

Step 2: Doping levels in the regions.
- The emitter is heavily doped to inject a large number of charge carriers (holes in the case of p-n-p).
- The base is very thin and lightly doped so that most of the injected charge carriers can pass through it.
- The collector is moderately doped and larger in size to collect the carriers and dissipate heat efficiently.

Step 3: Conclusion.
In a p-n-p transistor, the emitter is heavily doped and the collector is moderately doped.
Hence, the correct answer is: emitter is heavily doped and collector is moderately doped.