10 complex circuit analysis methods
Release time：2022-12-13
The prerequisite for circuit problem calculation is to correctly identify the circuit and understand the connection relationship between various parts. For more complex circuits, the original circuit should be simplified into an equivalent circuit for easy analysis and calculation. There are many ways to identify circuits,Shenzhen circuit board manufacturerThis paper introduces ten circuit analysis methods with concrete examples.
01 Feature recognition method
The characteristics of the series parallel circuit are: the current in the series circuit does not bifurcate, the potential at each point decreases gradually, the current in the parallel circuit bifurcates, and the two ends of each branch are equipotential, and the voltage between the two ends is equal. Circuit identification based on the characteristics of series parallel circuit is a basic method to simplify the circuit.
02 Telescopic overturning method
It is often possible to connect circuits in the laboratory in this way. The unimpeded conductor can be lengthened or shortened, or it can be turned over or turned over, or a branch can be turned over to another place, and both ends of the branch can remain unchanged when turning over; A wire can also slide along other wires from its node, but not over a component. This provides a method to simplify the circuit. We call this method expansion and turnover method.
03 Current trend method
Current is the core of analysis circuit. Starting from the positive pole of the power supply (the passive circuit can assume that the current flows from one end to the other end and flows out), along the direction of the current, through each resistor, walk around the external circuit for one cycle to the negative pole of the power supply. All the resistors that the current flows in sequence without bifurcation are in series, and all the resistors that the current flows in bifurcation are in parallel.
04 Equipotential method
In more complex circuits, it is often possible to find points with equal potential, and reduce all points with equal potential to one point, or draw them on a line segment. When there are non power supply components between two equipotential points, they can be removed without consideration; When a branch has neither power nor current, it can be canceled. We call this method of simple ratio circuit equipotential method.
05 Branch node method
A node is a junction of several branches in a circuit. The so-called branch node method is to number each node (convention: the positive pole of the power supply is the first node, and the nodes that pass through in sequence from the positive pole to the negative pole of the power supply are 1, 2, 3...). The branch starting from the first node is drawn to the negative pole of the power supply. There may be multiple branches (it is stipulated that different branches cannot pass through the same resistance repeatedly) that can reach the negative pole of the power supply. The principle of drawing is to draw branches with fewer nodes first, and then draw branches with more nodes. Then draw the branch starting from the second node according to this principle. By analogy for the rest of the times, the remaining resistance will be added according to the position of its two ends.
06 Geometric deformation method
Geometric deformation method is to carry out geometric deformation on a given circuit according to the characteristics of arbitrary extension, shortening, rotation or translation of wires in the circuit, further determine the connection relationship of circuit components, and draw an equivalent circuit diagram.
07 Removal of resistance method
According to the characteristics of the series parallel circuit, if any resistance is removed in the series circuit and no current passes through other resistors, these resistors are connected in series; In a parallel circuit, if any resistor is removed and current still flows through other resistors, these resistors are connected in parallel.
08 Independent branch road method
Let the current flow out from the positive pole of the power supply. Under the principle of not passing through the same element repeatedly, see how many of them flow back to the negative pole of the power supply, and then there are several independent branches. The residual resistance not included in the independent branch shall be added according to the position of its two ends. When this method is applied, the independent branch shall be selected to include the conductor.
09 Node bridging method
Number the nodes in the known circuit with 1, 2, 3... numbers in order of potential from high to low (the potential of the node connected to the positive pole of the power supply is high, the potential of the node connected to the negative pole of the power supply is low, and the nodes with equal potential use the same number and are combined into one point). Then rearrange the nodes according to the potential, and connect the components between the corresponding two nodes to draw the equivalent circuit.
10. Ammeter compensation method
If the complex circuit is connected with an ammeter, when the internal resistance of ammeter A and voltmeter V is not considered, because the internal resistance of the ammeter is zero, it can be removed and replaced by an open wire; As the internal resistance of the voltmeter is extremely large, it can be removed as an open circuit. Use the above method to draw the equivalent electricity and figure out the connection relationship, then add the ammeter to the corresponding position of the circuit.
