Tag Archives: NEGATIVE FEEDBACK

What are the advantages of negative feedback

(i) Highly stabilized gain.

(ii) Reduction in non-linear distortion.

(iii) Increased bandwidth,i.e.,improved frequency response.

(iv) Increased stability of circuit.

(v) Less amplitude distortion.

(vi) Less frequency distortion and less phase distortion.

(vii) Increases input impedance and decreases output impedance. In other words,the input and output impedance and decreases can be modified as required.

(viii) Reduces noise and less harmonic distortion.

(ix) The transfer gain Af of the amplifier with feedback can be stabilized against variations of the h-parameters of the transistor.

(x) The significant improvement in the frequency response and in the linearity of operation of the feedback amplifier compared with that of the amplifier without feedback.

Differences between positive feedback and negative feedback

POSITIVE FEEDBACK

(i) If the feedback signal (voltage or current) is applied in such a way that it is in phase with the input signal and thus increases it,then it is called a positive feedback.

(ii) it is a regenerative or direct feedback.

(iii) Positive feedback increases the gain of amplifier.

(iv) It produces excessive distortion.

(v) Positive feedback is used in oscillators.

NEGATIVE FEEDBACK 

(i) If the feedback signal (voltage or current) is applied in such a way that it is out of phase with the input signal and thus decreases it,then it is called negative feedback.

(ii)It is a degenerative or inverse feedback.

(iii) Negative feedback reduces gain of the amplifier.

(iv) It generates less distortion.

(v) Negative feedback is frequently used in small-signal as well as with large-signal amplifier circuits.