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Derive a relation between current gain o...

Derive a relation between current gain of common emitter amplifier.

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For a junction transistor, we know
`I_(e)=I_b+I_c` ...(i)
Current gain for common base amplifier,
`alpha=I_c//I_(e)`
Current gain for common emitter amplifier,
`beta=I_c//I_b`
From(i), `I_(e)/I_c=I_b/I_c+1` or `1/alpha=1/beta+1`
or `1/beta=1/alpha-1=(1-alpha)/alpha` or `beta=alpha/(1-alpha)`
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