Question

In a transistor amplifier, base-emitter junction is forward biased and collector-emitter junction is reverse biased. The current gain is

• A. \( \frac{\Delta I_E}{\Delta I_B} \)
• B. \( \frac{\Delta I_B}{\Delta I_E} \)
• C. \( \frac{\Delta I_B}{\Delta I_C} \)
• D. \( \frac{\Delta I_C}{\Delta I_B} \)

Hint:

In transistor circuits, the current gain \( \beta \) is defined as \( \frac{I_C}{I_B} \), where \( I_C \) is the collector current and \( I_B \) is the base current. The larger the current gain, the more effective the transistor is at amplifying signals.

Answer 1

The Correct Option is D

Step 1: Understanding current gain.
In a transistor amplifier, the current gain is defined as the ratio of the change in collector current \( \Delta I_C \) to the change in base current \( \Delta I_B \). This ratio indicates how much the base current is amplified in the collector circuit. The correct formula for current gain is \( \frac{\Delta I_C}{\Delta I_B} \).
Step 2: Conclusion.
Thus, the correct answer is (D) \( \frac{\Delta I_C}{\Delta I_B} \).