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Electronics — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsElectronics1 Mark
MCQ
The relation between $\alpha$ and $\beta$ parameters of current gains for a transistors is given by
  • A
    $\alpha=\frac{\beta}{1-\beta}$
  • ✓
    $\alpha=\frac{\beta}{1+\beta}$
  • C
    $\alpha=\frac{1-\beta}{\beta}$
  • D
    $\alpha=\frac{1+\beta}{\beta}$
✓

Answer

Correct option: B.
$\alpha=\frac{\beta}{1+\beta}$
$i_e=i_b+i_c \Rightarrow \frac{i_e}{i_c}=\frac{i_b}{i_c}+1$
$ \Rightarrow \frac{1}{\alpha}=\frac{1}{\beta}+1$
$ \Rightarrow\alpha=\frac{\beta}{(1+\beta)}$.

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