Question

A pnp transistor is used in common emitter mode in an amplifier circuit. When base current is charged by an amount ${\Delta I}_B$, the collector current changes by 4mA. If the current amplification factor is 60, then the value of ${\Delta I}_B$ is:

• A. $240mA$
• B. $66.6$ $\mu A$
• C. $60$ $\mu A$
• D. $15$ $\mu A$

Answer 1

Answer: (B)

$66.6$ $\mu A$

Current amplification factor is the change in collector current per unit change in base current.

$⟹\beta =\frac{\Delta I_C}{\Delta I_B}$

$⟹\Delta I_B=\frac{4mA}{60}=66.6\mu A$