The current comes out from the positive pole of the power supply and then goes through the consumer. Is it connected to the positive pole or negative pole of the consumer

The current comes out from the positive pole of the power supply and then goes through the consumer. Is it connected to the positive pole or negative pole of the consumer

The current direction of the external circuit is from positive to negative

Is there a series circuit of positive pole of power supply → switch → voltmeter → L2 → negative pole of power supply

This is the reading of the voltmeter. The voltage and current of the power supply can be read from the power supply, but the resistance of L2 is only the same as that of the voltmeter. At this time, the resistance of L2 is ignored. In this way, the resistance of the voltmeter can be calculated by R = V / I

Some people say that the current flows from the positive pole of the power supply to the negative pole of the power supply through the consumers. In this process, the current becomes weaker and weaker, and the consumers consume electricity

1. It's true that electrical appliances consume electricity. To be exact, electrical appliances consume electricity
2. The current at a certain point, flowing out = flowing in. If it is not equal, then the positive charge (or negative charge) at that point will accumulate, which looks like a capacitor can store energy
3. The current will not be weaker and weaker, only the electric energy will be used less and less

Does the current flow from the positive pole of the power supply, then through the switch, then through the consumer, and finally back to the negative pole of the power supply?

Outside the power supply, it flows out from the positive pole of the power supply, then through the switch, then through the consumer, and finally back to the negative pole of the power supply
Inside the power supply, it flows from the negative side of the power supply to the positive side