Introduction
Feedback circuits are commonly utilized in numerous electronic circuits. The feedback mechanism involves redirecting a portion or all of the amplifier’s output signal (either voltage or current) back to the input of the amplifier. This is done to compare the recycled output signal with the original input signal and to adjust the output accordingly.
This is the feedback process of the amplifier. The feedback signal that is fed back to the input serves to amplify the original input signal. Positive feedback amplifies the input signal, while negative feedback reduces it.
Classification
According to its circuit structure, it is divided into two types: current feedback circuits and voltage feedback circuits. Positive feedback circuits are mainly used in electronic oscillating circuits, while negative feedback circuits are utilized in various high and low frequency amplifying circuits.
Based on the circuit’s characteristics, feedback circuits can further be categorized into series feedback and parallel feedback.
Negative feedback has a significant impact on the performance of amplifiers, due to its wide application. The following are five effects of negative feedback on amplifiers:
- Improves the stability of the amplifier gain.
- Widens the passband of the amplifier.
- Reduces the distortion in the amplifier.
- Enhances the signal-to-noise ratio of the amplifier.
- Affects the output and input resistance of the amplifier.
