Question

A transistor is connected in C-E mode. If collector current is \( 72 \times 10^{-5} \, \text{A} \) and \( \alpha = 0.96 \), then base current will be:

• A. 30 \( \mu \text{A} \)
• B. 26 \( \mu \text{A} \)
• C. 28 \( \mu \text{A} \)
• D. 24 \( \mu \text{A} \)

Hint:

In a transistor, the base current can be calculated using the relationship \( I_B = \frac{I_C}{\alpha} \).

Answer 1

The Correct Option is A

Step 1: Relationship Between \( I_C \), \( I_B \), and \( \alpha \).
In a transistor, the relationship between collector current \( I_C \), base current \( I_B \), and \( \alpha \) is given by: \[ I_C = \alpha I_E \] where \( I_E \) is the emitter current. The emitter current is related to the base current by: \[ I_E = I_B + I_C \] From this, we can calculate the base current \( I_B \) as: \[ I_B = \frac{I_C}{\alpha} \] Substituting the given values: \[ I_B = \frac{72 \times 10^{-5}}{0.96} = 30 \times 10^{-6} \, \text{A} = 30 \, \mu \text{A} \] Step 2: Final Answer.
Thus, the base current is 30 \( \mu \text{A} \).