Question

Two amplifiers are connected one after the other in series (cascaded). The first amplifier has a voltage gain of $10$ and the second has a voltage gain of $20$. If the input signal is $0.01\, volt$, what is the output $ac$ signal ?

• A. $1.5\, V$
• B. $2\, V$
• C. $2.5\, V$
• D. $3.0\, V$

Answer 1

Answer: (B)

$2\, V$

Answer 2

Here, $A_{v_1} =10, A_{v_2} = 20, V_i = 0.01 \, V$ Net voltage gain of the two amplifiers connected in series is $A_v = A_{v_1} \times A_{v_2} =10 \times 20 = 200$ As $A_v = \frac{ \text{Output signal} (V_0)}{\text{Input signal} (V_i)}$ $\therefore \, \, V_0 = A_v \, V_i =(200)(0.01 V ) = 2 V$