Method steps for measuring DC current with a multimeter
1. Mechanical zero adjustment:
Like measuring resistance and voltage, the multimeter must be mechanically zeroed before use. The mechanical zero adjustment method is the same as the previous mechanical zero adjustment operation for measuring resistance and voltage. I won’t repeat it here, and the multimeters that are commonly used generally don’t need to be mechanically zeroed every time.
2. Select the range:
Roughly estimate the magnitude of the measured DC current according to the current of the power supply in the circuit to be tested, and select the range. If you don’t know the magnitude of the current, you should first use the highest current range (500mA range) to measure, and gradually switch to the lower current range until you find a suitable current range (the standard is the same as the measured voltage)
3. Measurement method:
When using the multimeter current block to measure the current, the multimeter should be connected in series in the circuit under test, because only in series connection can the current flowing through the ammeter be the same as the branch current under test. When measuring, the branch under test should be disconnected, and the red and black test leads of the multimeter should be connected in series between the two disconnected points. Special attention should be paid to the fact that the ammeter cannot be connected in parallel in the circuit under test, which is very dangerous and can easily burn out the multimeter. At the same time, pay attention to the polarity of the red and black gauge sticks. The red gauge stick should be connected to the current inflow end of the circuit under test, and the black gauge stick should be connected to the current outflow end of the circuit under test (same as DC voltage polarity selection).
4. Use scales and readings correctly.
When the multimeter measures DC current, the dial scale line is the same as when measuring voltage, which is the second track (the mA symbol is on the right side of the second scale line). Other scale features and reading methods are the same as measuring voltage.
If the measured current is greater than 500mA, the 5A range can be selected. Operation method: Set the switch to 500mA range, take out the red meter stick from the original "+" jack, and insert it into the jack marked 5A in the lower right corner of the multimeter to measure a large current below 5A.
