MCQ
In a $P N P$ transistor working as a common-base amplifier, current gain is $0.96$ and emitter current is $7.2\ mA$. The base current is
- A$0.4 mA$
- ✓$0.29 mA$
- C$0.2 mA$
- D$0.35 mA$
✓
Answer
Correct option: B.
$0.29 mA$
$ \alpha=\frac{i_c}{i_e}=0.96 \text { and } i=7.2 \mathrm{~mA} $
$\Rightarrow i_c=0.96 \times i_e=0.96 \times 7.2=6.91 \mathrm{~mA}$
$ \therefore i_e=i_c+i_b \Rightarrow 7.2=6.91+i \Rightarrow i=0.29 \mathrm{~mA} .$
$\Rightarrow i_c=0.96 \times i_e=0.96 \times 7.2=6.91 \mathrm{~mA}$
$ \therefore i_e=i_c+i_b \Rightarrow 7.2=6.91+i \Rightarrow i=0.29 \mathrm{~mA} .$
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