Four common methods for analyzing circuits

fish001

Four common methods for analyzing circuits [Copy link]

Electronic circuit diagrams are used to represent the composition, structure, nominal values of components and other information of actual electronic circuits. Circuit diagrams can tell us the actual situation of circuits. In this way, when we analyze circuits, we don't have to turn the physical object over and over again, but just take a drawing. When designing circuits, we can also calmly do it on paper or on a computer, confirm that it is perfect, and then actually install it, debug and improve it until it succeeds. We can also use advanced computer software to assist in circuit design, and even conduct virtual circuit experiments, which greatly improves work efficiency.

Here are four commonly used methods for analyzing circuits, as well as the circuit types and analysis steps suitable for each method. 1. Time constant analysis method The time constant analysis method is mainly used to analyze the properties of the circuit composed of R, L, C and semiconductor diodes. The time constant is a parameter that reflects the speed of energy accumulation on the energy storage element. If the time constant is different, although the form and connection of the circuit are similar, the role played in the circuit is different. Common ones include coupling circuits, differential circuits, integral circuits, clamping circuits and peak detection circuits. 2. Frequency Characteristics Analysis Method Frequency characteristics analysis method is mainly used to analyze whether the frequency of the circuit itself is compatible with the frequency of the signal it processes. In the analysis, its center frequency, upper and lower limit frequencies and bandwidth should be simply calculated. Through this analysis, the properties of the circuit can be known, such as filtering, notching, resonance, frequency selection circuit, etc. 3. DC equivalent circuit analysis method When analyzing the circuit principle, it is necessary to clarify the DC path and AC path in the circuit. The DC path refers to the static bias of each semiconductor triode and integrated circuit when there is no input signal, that is, their static operating point. The AC circuit refers to the path of AC signal transmission, that is, the origin and development of the AC signal. In the actual circuit, the AC circuit and the DC circuit coexist in the same circuit. They are both related and different from each other.

The DC equivalent analysis method is a method of analyzing the DC system of the circuit being analyzed separately. When performing DC equivalent analysis, the circuit's processing function for the input AC signal is completely ignored, and only the static DC current and voltage directly caused by the DC voltage of the power supply and their mutual relationship are considered.

When performing DC equivalent analysis, the DC equivalent circuit diagram should be drawn first. The following principles should be followed when drawing the DC equivalent circuit diagram: capacitors are all treated as open circuits, inductors whose DC resistance can be ignored should be regarded as short circuits, and inductors whose resistance components cannot be ignored can be equivalent to resistors. Take the voltage after step-down and decoupling as the power supply voltage of the equivalent circuit; regard the semiconductor diode in the reverse bias state as an open circuit.

4. AC equivalent circuit analysis method

The AC equivalent circuit analysis method is a method of separating the AC system in the circuit from the circuit and analyzing it separately.

When performing AC equivalent analysis, the AC equivalent circuit diagram should be drawn first. The following principles should be followed when drawing an AC equivalent circuit diagram: treat the power supply as a short circuit, treat all AC bypass capacitors as short circuits, and treat all DC isolation couplers as short circuits.