Explain principle of feedback amplifier.

Explain principle of feedback amplifier.
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1 Answer

Answer :

Block diagram of feedback amplifier:-

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Explanation:- * “Feedback” is a process of injecting some energy from the output and then it back to the input. The amplifier which use the feedback principle are called feedback amplifier“. * Depending upon whether the feedback signal increases or decreases the input signal, there are 2 basic types of feedback: Positive feedback and Negative feedback. 


From the above figure, the gain of the amplifier is represented as A. the gain of the amplifier is the ratio of output voltage Vo to the input voltage Vi . The feedback network extracts a voltage Vf = β Vo from the output Vo of the amplifier. This voltage is added for positive feedback and subtracted for negative feedback, from the signal voltage Vs. Now,

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The quantity β = Vf /Vo is called as feedback ratio or feedback fraction.

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