In a transistor

Options

A. (a)emitter is more highly doped than collector
B. (b)collector is more highly doped than emitter
C. (c)both emitter and collector are equally doped
D. (d)none of these

Answer

To solve the question regarding the statements about a transistor, we will analyze the properties and characteristics of the three regions of a transistor: the emitter, base, and collector.

### Step-by-Step Solution:

1. **Identify the Regions of a Transistor**:
- A transistor consists of three main regions: the emitter, base, and collector.
- For a Bipolar Junction Transistor (BJT), these regions can be arranged in two configurations: NPN or PNP.

2. **Understand the Doping Levels**:
- The emitter is heavily doped to inject carriers (electrons or holes) efficiently into the base.
- The base is lightly doped and very thin, which allows for the majority of carriers to pass through to the collector.
- The collector is moderately doped, which allows it to collect the carriers from the base.

3. **Analyze the Statements**:
- **Statement 1**: "Emitter is more highly doped than collector."
- This statement is true because the emitter is heavily doped compared to the collector, which is moderately doped.
- **Statement 2**: "Collector is more highly doped than emitter."
- This statement is false as the emitter is heavily doped while the collector is only moderately doped.
- **Statement 3**: "Base is thinner than both emitter and collector."
- This statement is true because the base is designed to be thinner than both the emitter and collector.
- **Statement 4**: "Collector is thinner than emitter."
- This statement is false as the collector is wider than the emitter.

4. **Conclusion**:
- The correct statements regarding the transistor are:
- Emitter is more highly doped than collector.
- Base is thinner than both emitter and collector.

### Final Answer:
The correct statement about the transistor is: "Emitter is more highly doped than collector."