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A transistor is operated in common-emitter configuration at $V_C$ = 2 V such that a change in the base current from 100 $\mu$A to 200 $\mu$A produces a change in the collector current from 5 mA to 10 mA. The current gain is
A
50
B
75
C
100
D
150
Detailed Solution
Current gain in common-emitter configuration: $\beta = \frac{\Delta I_C}{\Delta I_B}$
$\Delta I_C = 10 - 5 = 5$ mA $= 5\times10^{-3}$ A
$\Delta I_B = 200 - 100 = 100\ \mu$A $= 100\times10^{-6}$ A
$\beta = \frac{5\times10^{-3}}{100\times10^{-6}}$
$\beta = 50$
$\Delta I_C = 10 - 5 = 5$ mA $= 5\times10^{-3}$ A
$\Delta I_B = 200 - 100 = 100\ \mu$A $= 100\times10^{-6}$ A
$\beta = \frac{5\times10^{-3}}{100\times10^{-6}}$
$\beta = 50$