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 mho 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 mho and current gain 20, the voltage gain will be : (A) (5/4) G (B) (2/3) G (C) 1.5 G (D) (1/3) G

Tardigrade Admin · Accepted Answer

Voltage gain Av = (Δ Vc/Δ VB) = (RLΔ Ic/Δ VB) = gmRL (AV1/Av2) = (gm1/gm2)⇒ (G/Av2) = (0.03/0.02)⇒ Av2 = (2/3)G

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

$\frac{5}{4} G$

$\frac{2}{3} G$

$1.5 G$

$\frac{1}{3} G$

Voltage gain $A_{v} = \frac{Δ V _{c}}{Δ V _{B}} = \frac{R _{L} Δ I _{c}}{Δ V _{B}} = g_{m} R_{L}$
$\frac{A _{V 1}}{A _{v 2}} = \frac{g _{m 1}}{g _{m 2}} \Rightarrow \frac{G}{A _{v 2}} = \frac{0.03}{0.02} \Rightarrow A_{v 2} = \frac{2}{3} G$

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

45​G

32​G

1.5G

31​G