Semiconductor Electronics Materials Devices and Simple Circuits - Result Question 77
79. In the study of transistor as amplifier, if $\alpha=\frac{I_C}{I_E}$ and $\beta=\frac{I_C}{I_B}$, where, $I_C, I_B$ and $I_E$ are the collector, base and emitter currents, then
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(a) $\beta=\frac{(1+\alpha)}{\alpha}$
(b) $\beta=\frac{(1-\alpha)}{\alpha}$
(c) $\beta=\frac{\alpha}{(1-\alpha)}$
(d) $\beta=\frac{\alpha}{(1+\alpha)}$
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Answer:
Correct Answer: 79. (c)
Solution:
- (c) As we know that $I_e=I_c+I_b$
Divide both side by $I_e$
$\frac{I_e}{I_c}=1+\frac{I_b}{I_c} \Rightarrow \frac{1}{\alpha}=1+\frac{1}{\beta}$
$\beta=\frac{\alpha}{1-\alpha}$
