Question

In a p-n-p transistor working as common base amplifier, current gain is 0.96 and emitter current is 7.2 mA. Then base current will be:

• A. 0.2 mA
• B. 0.29 mA
• C. 0.35 mA
• D. 0.4 mA

Answer 1

Answer: (B)

0.29 mA

Answer 2

Here, current gain $\alpha =0.96$ and emitter current ${{i}_{e}}=7.2\,mA$ from the relation of current gain $\alpha =0.96=\frac{{{I}_{c}}}{{{I}_{e}}}=\frac{{{I}_{c}}}{7.2},$ So ${{I}_{c}}=0.96\times 7.2=6.91\,mA$ Hence the base current ${{I}_{b}}={{I}_{e}}-{{I}_{c}}=7.2-6.91=0.29\,mA$