Question

In an n-p-n transistor circuit, the collector current is 10 mA. If 90% of the electrons emitted reach the collector

• A. the emitter current will be 9 mA
• B. the emitter current will be 11 mA
• C. the base current will be 1mA
• D. the base current will be -1mA

Answer 1

Answer: (C)

the base current will be 1mA

Answer 2

$i_e$ = 10mA = (0.9) i_e [Giventhat $i_e$ is 90% of $i_e$]
$\therefore i_e = \frac {10}{0.9}mA = 11mA$
and $i_b = i_e - i_c = (11 - 10)mA = 1 mA$