The current gain for a transistor working as common base amplifier is 0.96 . If the emitter current is $7.2…
The current gain for a transistor working as common base amplifier is 0.96 . If the emitter current is $7.2 \mathrm{~mA}$, then the base current is
- $0.29 \mathrm{~mA}$
- $0.35 \mathrm{~mA}$
- $0.39 \mathrm{~mA}$
- $10 \mathrm{~mA}$
Solution
Given, current gain, $\alpha=0.96$
Emitter current, $I_E=7.2 \mathrm{~mA}=7.2 \times 10^{-3} \mathrm{~A}$
We know that,
$
\begin{aligned}
\alpha & =I_C / I_E \\
\Rightarrow \quad I_C & =\alpha \times I_E=0.96 \times 7.2 \times 10^{-3} \mathrm{~A}=6.91 \times 10^{-3} \mathrm{~A} \\
\text { Also, } I_E & =I_C+I_B \\
\Rightarrow \quad I_B & =I_E-I_C=(7.2-6.91) \times 10^{-3} \mathrm{~A} \\
& =0.29 \times 10^{-3} \mathrm{~A}=0.29 \mathrm{~mA}
\end{aligned}
$
Asked in: AP EAMCET 2021 (25 Aug Shift 1)
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