In a common emitter transistor amplifier, the input resistance of a tr – InterviewSolution

1.	In a common emitter transistor amplifier, the input resistance of a transistor is `1000Omega`. On changing its base current by 10muA, the collector current increases by `2mA`. If a load resistance of `5kOmega` is used in the circuit, calculate: (i) the currnet gain (ii)the voltage gain of the amplifier.
Answer» Here, `R_(i)=1000Omega, DeltaI_=10muA=10^(-5)A`, `DeltaI_C=2mA=2xx10^(-3)A` `R_(0)=5kOmega=5xx10^(3)Omega`. (i) Current gain, `beta=(DeltaI_C)/(DeltaI_B)=(2xx10^(-3))/(10^(-5))=200` (ii) Voltage gain, `A_(V)=betaR_(0)/R_(i)=(200xx5xx10^(3))/1000=1000`

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