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, calculate the output ac signal.

Answer 1

Voltage gain of the first amplifier, V1 = 10
Voltage gain of the second amplifier, V2 = 20
Input signal voltage, Vi = 0.01 V
Output AC signal voltage = Vo
The total voltage gain of a two-stage cascaded amplifier is given by the product of voltage gains of both the stages, i.e.,
$V = V_1 × V_2$
$V = 10 × 20 = 200$
We have the relation:
$V = \frac{V_0}{V_i}$
$V_0 = V × V_i$
$V_0 = 200 × 0.01$
$V0 = 2 V$
Therefore, the output AC signal of the given amplifier is 2 V.