Question

The current gain of a transistor in common emitter mode is $35$. The change in collector current is $140$mV at constant collector to emitter voltage. The change in the base current will be.

• A. $10$mA
• B. $2$mA
• C. $0.1$mA
• D. $4$mA

Answer 1

The correct option is D $4$mA

Current gain of a transistor in CE mode is given by
$\beta ={\left(\frac{\Delta I_C}{\Delta I_B}\right)}_{V_{CE}=constant}$
$\therefore \Delta I_B=\frac{\Delta I_C}{\beta }=\frac{140\times {10}^{-3}}{35}$
$=4\times {10}^{-3}A=4mA$.