Question

The voltage gain and the current amplification factor of a transistor in common emitter configuration are \( 300 \) and \( 60 \) respectively. If the collector resistance is \( 5 k\Omega \), then the base resistance is:

• A. \( 5 k\Omega \)
• B. \( 25 k\Omega \)
• C. \( 2 k\Omega \)
• D. \( 1 k\Omega \)

Hint:

For common emitter transistors, use: \[ A_v = \beta \frac{R_C}{R_B} \] to determine base resistance.

Answer 1

The Correct Option is C

Step 1: Voltage Gain Formula The voltage gain \( A_v \) for a transistor in common emitter configuration is: \[ A_v = \beta \frac{R_C}{R_B} \] where: - \( \beta = 60 \) (current gain), - \( R_C = 5k\Omega \) (collector resistance), - \( A_v = 300 \). Step 2: Solving for \( R_B \) \[ 300 = 60 \times \frac{5000}{R_B} \] \[ R_B = \frac{60 \times 5000}{300} \] \[ = \frac{300000}{300} = 2000 \Omega = 2 k\Omega \] Conclusion Thus, the correct answer is: \[ 2 k\Omega \]