For a common emitter configuration, if $\alpha$ and $\beta$ have their usual meanings, the incorrect relationship between $\alpha$ and $\beta$ is:

(A) $\alpha=\frac{\beta}{1-\beta}$; (C) $\alpha=\frac{\beta^{2}}{1+\beta^{2}}$

(B) $\alpha=\frac{\beta}{1+\beta}$

(D) $\frac{1}{\alpha}=\frac{1}{\beta}+1$

JEE Main · 2016 · 03 Apr 2016 · Offline · Semiconductors

For a common emitter configuration, if

α

and

β

have their usual meanings, the incorrect relationship between

α

and

β

is:

Answer: (A), (C)

For a common-emitter transistor

α = \frac{β}{1 + β}

and

\frac{1}{α} = 1 + \frac{1}{β}

, so (B) and (D) are correct. (A)

α = β / (1 - β)

has the wrong sign, and (C)

α = β^{2} / (1 + β^{2})

is never valid — both incorrect.

JEE Main · 2016 · 03 Apr 2016 · Offline · One or more correct options