Question

In a silicon transistor, a change of $7.89mA$ in the emitter current, produces a change of $7.8mA$ in the collector current. The change in the base current is necessary to produce an equivalent change in the collector current

• A. $90mA$
• B. $90A$
• C. $90\mu A$
• D. $0.9mA$

Answer 1

The correct option is C $90\mu A$

Given that:
$I_e=7.89mA$
$I_c=7.8mA$
In transistors,
$I_e=I_b+I_c$
$\Delta I_e=\Delta I_b+\Delta I_c$
$\Delta I_b=\Delta I_e-\Delta I_c$
$\therefore I_b=7.89-7.8=0.09mA=90\mu A$