For a common-emitter transistor amplifier, the current gain is 60 . If the emitter current is $6.6…
For a common-emitter transistor amplifier, the current gain is 60 . If the emitter current is $6.6 \mathrm{~mA}$, then its base current is
- $6.492 \mathrm{~mA}$
- $0.108 \mathrm{~mA}$
- $4.208 \mathrm{~mA}$
- $0.343 \mathrm{~mA}$
Solution
$\begin{aligned} & \text { Using } l_{\mathrm{E}}=l_{\mathrm{B}}+l_{\mathrm{C}} \\ & \Rightarrow l_{\mathrm{B}}=l_{\mathrm{E}}-l_{\mathrm{C}} \\ & =6.6 \times 10^{-3}-60 l_{\mathrm{B}} \\ & \Rightarrow \quad l_{\mathrm{B}}+60 l_{\mathrm{B}}=6.6 \times 10^{-3} \\ & \text { or } \quad 61 l_{\mathrm{B}}=6.6 \times 10^{-3} \\ & \therefore \quad l_{\mathrm{B}}=\frac{6.6 \times 10^{-3}}{61} \simeq 0.108 \mathrm{~mA} \\ & =0.108 \times 10^{-3} \\ & =0.108 \mathrm{~mA}\end{aligned}$
Asked in: AP EAMCET 2016
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