Current gain of a transistor in common base mode is 0.95. Its value in coinmon emitter mode is

Options

A. 0.95
B. 1.5
C. 19
D. `(19)^(-1)`

Explanation

To find the current gain of a transistor in common emitter mode (β) when the current gain in common base mode (α) is given as 0.95, we can use the relationship between α and β.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- The current gain in common base mode is denoted by α.
- The current gain in common emitter mode is denoted by β.

2. **Given Information**:
- α = 0.95 (current gain in common base mode).

3. **Use the Relationship Between α and β**:
- The relationship between α and β is given by the formula:
\[ \alpha = \frac{\beta}{\beta + 1} \]
- Rearranging this formula to solve for β gives:
\[ \alpha(\beta + 1) = \beta \]
\[ \alpha\beta + \alpha = \beta \]
\[ \beta - \alpha\beta = \alpha \]
\[ \beta(1 - \alpha) = \alpha \]
\[ \beta = \frac{\alpha}{1 - \alpha} \]

4. **Substituting the Value of α**:
- Now substitute the value of α into the equation:
\[ \beta = \frac{0.95}{1 - 0.95} \]
\[ \beta = \frac{0.95}{0.05} \]

5. **Calculating β**:
- Perform the division:
\[ \beta = 19 \]

### Final Answer:
The current gain in common emitter mode (β) is **19**.

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