In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance $$0.03$$ mho and current gain $$25$$. If the above transistor is replaced with another one with transconductance $$0.02$$ rnho and current gain $$20$$, the voltage gain will be

Question

In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance $$0.03$$ mho and current gain $$25$$. If the above transistor is replaced with another one with transconductance $$0.02$$ rnho and current gain $$20$$, the voltage gain will be

Infinity Learn · Accepted Answer

Voltage $$gain=$$ Current gain × Resistance gainAυ$$=$$β×RoutRin Transconductance, $$gm=$$βRin  or  $$Rin=$$βgm ∴  Aυ$$=gm$$  Rout For  first  case, Aυ$$=G$$,  $$gm=0.03mho$$, β$$=25$$ ∴  $$G=0.03Rout$$                   −−−(i) For  second  case, Aυ$$=G$$', $$gm=0.02mho$$,β$$=20$$ ∴  G'$$=0.02Rout$$                   −−−(ii) Divide  (ii)  by  (i), we get G'$$G=23$$  or  G'$$=23G$$

In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 rnho and current gain 20, the voltage gain will be

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