# Four common methods of circuit analysis

- Sep 22, 2018-

Common methods of analyzing circuits are as follows:

1. Direct current equivalent circuit analysis method

When analyzing the circuit principle, make clear the dc and ac circuits in the circuit.Dc path refers to the static bias of semiconductor triode and integrated circuit when there is no input signal, that is, their static working point.Ac circuit refers to the path of ac signal transmission, that is, the origin and development of ac signals.

In the actual circuit, the alternating circuit and the direct current circuit coexist in the same circuit.

Dc equivalent analysis method, that is, to the analysis of the circuit to the separate analysis of the dc system a kind of method, when the dc equivalent analysis, completely regardless of the circuit of input ac signal processing functions, only consider caused directly by the dc voltage static dc current, voltage, and the relationship between them.

In the dc equivalent analysis, the dc equivalent circuit diagram should be drawn first.When drawing dc equivalent circuit diagram, the following principles should be followed: capacitors should be treated as open circuit, inductors that can ignore dc resistance should be treated as short circuit, inductors that cannot ignore resistance components can be equivalent to resistance.The voltage after voltage dropping and decoupling is taken as the supply voltage of the equivalent circuit.Semiconductor diodes in the antiskew state are treated as open circuit.

2. Alternating current equivalent circuit analysis:

The method of ac equivalent circuit analysis is to separate the ac system from the circuit and analyze it separately.

In the ac equivalent analysis, the ac equivalent circuit diagram should be drawn first.To draw the ac equivalent circuit diagram, the following principles should be followed: the power source should be regarded as short circuit, the capacitors along the ac bypass should be regarded as short circuit, and the blocking coupler should be regarded as short circuit.

3. Time constant analysis

The time constant analysis method is mainly used to analyze the properties of R, L, C and semiconductor diode constituent circuits. The time constant is a parameter reflecting the speed of energy accumulation on energy storage components.Common are coupling circuit, differential circuit, integral circuit, clamp circuit and peak detection circuit.

4. Frequency characteristic analysis:

Frequency characteristic analysis is mainly used to analyze whether the frequency of the circuit itself is appropriate to the frequency of the signal it processes.In the analysis, the center frequency, upper and lower frequency and frequency band width should be calculated.By this analysis, the properties of the circuit, such as filtering, notch, resonance, frequency selection circuit, etc