Pay attention when using ammeter

(1) The ammeter is a kind of instrument for measuring current, which generally has two ranges and three terminals;
(2) When the ammeter is used, it should be connected in series in the circuit, and the current flows in from the "+" terminal and out from the "-" terminal;
(3) When reading the ammeter, you should see the selected range and the corresponding graduation value clearly, and read according to the position of the pointer;
(4) The internal resistance of the ammeter is very small, which is equivalent to a wire. It is absolutely not allowed to connect the ammeter directly to the two poles of the power supply, which will cause a short circuit of the power supply

How to judge whether it is internal connection or external connection? Why choose internal connection when the ammeter changes significantly?
When the voltmeter changes significantly, the external connection should be used?

Remember "big inside, small outside"
Specific meaning:
The internal connection method is suitable for measuring large resistance, and the measured value is greater than the true value
The external small to external connection method is suitable for measuring small resistance, and the measured value is less than the real value

Why is an ammeter connected internally when measuring internal resistance by voltammetry?

Yes
The internal connection method is that the ammeter and the resistance to be measured are both in the two terminals of the voltmeter
Since the measured resistance is internal, the power supply is regarded as the measured resistance rather than the sliding rheostat

Pay attention when using ammeter