Feedback circuit

Returns the output X of the amplifying circuit to the input circuit in a certain way, which is called feedback.

Positive feedback and negative feedback

Positive feedback is used to increase the output after feedback is introduced.

Negative feedback is called to reduce the output after negative feedback is introduced.

Adding a net input is called positive feedback.

Reducing the net input is called negative feedback.

 

The feedback only contains the communication component.

Only the DC feedback is contained in the feedback.

DC negative feedback is used to stabilize static work points.

 

Four ways to exchange negative feedback

The feedback is taken from the output voltage, which is called voltage feedback.

The feedback is taken from the output current, which is called the current feedback.

Series feedback and parallel feedback

The feedback amount and input amount are superimposed in the form of voltage, called Series negative feedback.

The feedback amount and input amount are superimposed in the form of current, which is called parallel negative feedback.

 

Voltage series Negative Feedback amplification circuit

 

Current series Negative Feedback amplification circuit

Voltage parallel negative feedback amplification circuit

Current parallel negative feedback amplification circuit

Feedback circuit