Use voltmeter and ammeter to measure resistance. Why use sliding rheostat in this experiment

Use voltmeter and ammeter to measure resistance. Why use sliding rheostat in this experiment

Change the current and voltage, measure the average value of resistance many times

It's a very complicated physics circuit diagram of junior high school. It's about moving the sliding rheostat. It's about the change of voltmeter and ammeter. What do you think about it in series and parallel
For example, if it's in series, will the resistance and current between the resistance and current become larger and larger? If it's in parallel, will the resistance become larger and the voltage become smaller? How to see which electrical appliance the voltmeter measures in a complex series circuit, and how to see in a complex parallel circuit, Ammeter in the end to test which electrical ah? Sometimes in a very complex parallel circuit, I see the ammeter on both sides of the wire are connected with electrical appliances, do not know which in the end to test! To test! Ask for help!

Ah, little brother, it seems that you don't know anything about physics! It's not that I beat you. You don't understand the most basic of physics, and the deeper one is even less. Let me tell you something: the greater the resistance, the smaller the current. In parallel connection, the greater the resistance, and the greater the voltage at both ends. In a complex circuit, it's not that the voltmeter measures which electrical appliance, but that it measures two

How to solve the problem that the circuit is changed from series connection to parallel connection, and the indication change of ammeter and voltmeter after moving the sliding rheostat in the circuit?
Sliding rheostat Hua came and went, I was completely dizzy
Is there any way? Find the correct solution. If there is one on PS, don't copy and paste it. I've seen it all

I'll tell you a trick. It's the same as channeling. It's the same with the rheostat. It's the opposite with the rheostat