If an emitter current is changed by 4 mA, the collector current changes by 3.5 mA. The value of $\beta$ will be :
Solution
Given, emitter current, I<sub>E</sub> = 4 mA<br/><br/>Collector current, I<sub>C</sub> = 3.5 mA<br/><br/>Current gain in common base amplifier,<br/><br/>$\alpha = {{{I_C}} \over {{I_E}}}$<br/><br/>$\Rightarrow \alpha = {{3.5} \over 4} = {7 \over 8}$<br/><br/>Also, current gain in common emitter amplifier, <br/><br/>$\beta = {\alpha \over {1 - \alpha }}$<br/><br/>$\Rightarrow \beta = {{7/8} \over {1 - 7/8}}$<br/><br/>$\beta = 7$
About this question
Subject: Physics · Chapter: Electronic Devices · Topic: Transistors
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