Question

The current gain for a common emitter amplifier is 69 if the emitter current is 7 mA, the base current is

• A. $0.1mA$
• B. 1 mA
• C. $0.2mA$
• D. 2 mA

Answer 1

Answer: (A)

$0.1mA$

Answer 2

: current gain, $\beta = \frac{I_{C}}{I_{B}}$

For common emitter configuration

$I_{E} = I_{C}$

$\therefore I_{C} = 7mA$

$\therefore I_{B} = \frac{I_{C}}{\beta} = \frac{7 \times 10^{- 3}A}{69} = 0.1mA$