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# In a common base amplifier current gain is $0.96$ and emitter current is $7.2\;mA$. The base current is

$(a)\;35\;mA \\ (b)\;0.35\;mA \\ (c)\;29\;mA \\ (d)\;0.29 mA$
Can you answer this question?

Current gain $\alpha =\large\frac{i_1}{i_e}$
$\alpha =0.96$
$i_e =7.2 mA$
$i_c=0.96 \times 7.2$
$\quad= 6.91\;mA$
$i_e =i_c+i_b$
$\therefore i_b =i_c+ i_b$
$\qquad= 7.2 -6.91$
$\qquad= 0.291\;mA$
Hence d is the correct answer.
answered Jan 28, 2014 by