How to identify the circuit?

Judging the power supply series and parallel circuits, there are roughly the following methods:

First, the current flow method
Starting from the positive (or negative) side of the power supply, the path through which the current passes is analyzed along the direction of current flow. If only one path passes through all the electrical appliances, the circuit is connected in series; if the current branches somewhere and merges at another, the circuit between the branches and the junction is parallel.
This method is a commonly used method in circuit analysis.

Second, the definition method
Direct judgment based on the definition of series and parallel circuits. The series circuit is connected end to end with electrical appliances and then connected to the circuit; the parallel circuit is connected to the two ends of the electrical device and then connected to the circuit.
This method is suitable for simpler circuits.

Third, the demolition method
The series circuit has only one current path. If one of the electrical appliances is disconnected, other electrical appliances cannot work. The parallel circuit has multiple current paths. If one of the electrical appliances is disconnected, other electrical appliances work as usual.

Fourth, go to the table method
If there are ammeters or voltmeters in the circuit, you can remove them. The method of removing is as follows: the position of the voltmeter is regarded as an open circuit (because the internal resistance of the voltmeter is large, almost no current flows); the position of the ammeter is connected by wires (since the internal resistance of the ammeter is small, the resistance can be regarded as zero).
This method is suitable for circuits with an electric meter.

Five, equivalent method (wire stretching method)
For complex circuits, the wires can be viewed as being stretchable and contractible. After equivalent processing, the connection and level of the circuit can be made more intuitive.