In CE configuration transistor, the current gain

Options

A. Is always less than 1
B. Is always infinity
C. Is always greater than 200
D. Lies in between 20 and 200

Answer

To solve the question regarding the current gain in a common emitter (CE) configuration transistor, we will follow these steps:

### Step 1: Understand the Definition of Current Gain
The current gain (beta, β) in a common emitter configuration is defined as the ratio of the change in collector current (ΔIC) to the change in base current (ΔIB). Mathematically, it is expressed as:
\[ \beta = \frac{\Delta I_C}{\Delta I_B} \]

### Step 2: Analyze the Options Given
The question provides four options regarding the value of beta:
1. Always less than 1
2. Always infinity
3. Always greater than 200
4. Lies between 20 and 200

### Step 3: Evaluate Each Option
- **Option 1**: "Always less than 1" - This is incorrect because beta is typically greater than 1 for common emitter transistors.
- **Option 2**: "Always infinity" - This is also incorrect as beta is a finite value.
- **Option 3**: "Always greater than 200" - This is not true; while some transistors may have high beta, it is not universally greater than 200.
- **Option 4**: "Lies between 20 and 200" - This is the correct option. For most common emitter transistors, the value of beta typically falls within this range.

### Step 4: Conclusion
Based on the analysis, the correct answer is:
**Option 4: Lies between 20 and 200.**