Question

In a transistor (common emitter configuration) the ratio of power gain to voltage gain is ( $\alpha$ and $\beta$ are current ratios)

• A. $\frac{\beta}{\alpha}$
• B. $\alpha\beta$
• C. $\alpha$
• D. $\beta$

Hint:

Power = Current $\times$ Voltage. Thus, Power Gain = Current Gain $\times$ Voltage Gain. In CE mode, Current Gain is always $\beta$.

Answer 1

The Correct Option is D

Step 1: Concept
Power Gain ($A_p$) in a transistor is the product of Current Gain and Voltage Gain ($A_v$).

Step 2: Meaning
$A_p = \text{Current Gain} \times A_v \implies \frac{A_p}{A_v} = \text{Current Gain}$.

Step 3: Analysis
In Common Emitter (CE) configuration, the current gain is defined as $\beta$ (the ratio of change in collector current to change in base current).

Step 4: Conclusion
The ratio of power gain to voltage gain is $\beta$. Final Answer: (D)