Question

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

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

Hint:

The common emitter current gain is the ratio of change in collector current to change in base current.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In the normal working of a transistor amplifier, the emitter-base junction is forward biased and the collector-base junction is reverse biased.

Step 2: Detailed Explanation:
The current gain \(\beta\) is the ratio of change in collector current to change in base current: \(\beta = \dfrac{\Delta I_C}{\Delta I_B}\).

Step 3: Check the options.
Option (B) is the inverse. Option (C) divides emitter current change by base current change, which equals \(\beta + 1\). Option (D) is the inverse of that kind of ratio.

Final Answer:
The current gain is \(\dfrac{\Delta I_C}{\Delta I_B}\), option (A). \[ \boxed{\frac{\Delta I_C}{\Delta I_B}} \]