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

Hello Students,

◆ Answer -

Output AC signal = 2 V

● Explanation -

# Given -

Vi = 0.01 V

Av1 = 10

Av2 = 20

# Solution -

Output voltage of 1st amplifier is -

Vo = Vi × Av1

Vo = 0.01 × 10

Vo = 0.1 V

Output voltage of 1st amplifier will be input voltage for 2nd amplifier.

Vi' = Vo

Output voltage of 2nd amplifier is -

Vo' = Vi' × Av2

Vo' = 0.1 × 20

Vo' = 2 V

Therefore, output AC signal is 2 V.

Best luck dear...

Answer 2

➙ Given :-

• Vi = 0.01 V
• Av1 = 10
• Av2 = 20

➙ To Find :-

• The output AC signal = ?

➙ Solution :-

• Voltage gain of first amplifier V1 = 10
• Voltage gain of second amplifier V2 = 20

▶ Input signal voltage Vi = 0.01 V

▶ Output AC signal voltage = Vo

_[ considering o = nought ]

▶The total voltage gain of two stage cascaded amplifier is given by the product of voltage gains of both the stages i.e,

• V = V1 × V2
• V = 10 × 20
• V = 200

▶We have the relation :-

• V = Vo / V1
• Vo = V × Vi
• Vo = 200 × 0.01
• Vo = 2V

▶Therefore The output AC signal of the given amplifier is 2V !

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