Generally, the greater the feedback depth is introduced, the better the improvement of circuit performance, such as the improvement of gain stability, the broadening of the passband, the reduction of nonlinear distortion, the increase of input resistance and the reduction of output resistance. However, the greater the feedback depth, the greater the gain attenuation of the circuit, so the negative feedback is at the expense of the gain in exchange for improved circuit performance. Therefore, high gain amplifier circuits such as integrated operational amplifiers should be used. At the same time, the selection of the feedback coefficient in the feedback circuit should also be determined according to the actual requirements. In addition, the introduced negative feedback has different effects on the performance of the circuit, and in order to make the negative feedback have a significant effect on the performance of the circuit, there are different requirements for different signal sources and different loads, so the design is negative. When the feedback amplifier circuit is used, appropriate negative feedback should be introduced according to the needs and purposes. The following are some principles that should be mastered in the design.

1. When the signal source is a constant voltage source or a voltage source with a small internal resistance, a series negative feedback should be introduced. When the signal source is a constant current source or a voltage source with a large internal resistance, parallel negative feedback should be introduced. In this way, the adjustment effect of the introduced negative feedback can be fully exerted.

2. When the load needs a stable voltage signal, voltage negative feedback should be introduced. When the load needs a stable current signal, current negative feedback should be introduced.

3. When in order to improve the input resistance of the circuit, the series negative feedback should be introduced. When the output resistance of the circuit is reduced, the voltage negative feedback should be introduced.

4. If it is necessary to convert the current signal into a voltage signal, the voltage should be connected to the amplifier in parallel with the negative feedback. If the voltage signal needs to be converted into a current signal, the current series negative feedback should be introduced in the amplifier circuit.

5. In order to stabilize the static working point of the circuit, DC negative feedback should be introduced.


Recommended reading: Triode amplifier circuit principle

Power Inverter

Power Inverter,Sine Wave Solar Power Converter,Pure Sine Wave Solar Inverter,Pure Sine Wave Power Inverter

Zhejiang Kaimin Electric Co., Ltd. , http://www.ckmineinverter.com

Posted on