Method steps for DC current measurement with a multimeter
1. Mechanical zeroing:
Like measuring resistance and voltage, a multimeter must be mechanically zeroed before use. The mechanical zeroing method is the same as the previous mechanical zeroing operation for measuring resistance and voltage. This will not be repeated here, and commonly used multimeters do not need to be mechanically zeroed every time.
2. Select range:
Roughly estimate the magnitude of the measured DC current based on the current of the power supply in the circuit under test, and select the measurement range. If you are not sure about the magnitude of the current, you should first measure it with the highest current level (500mA level), gradually switch to the lower current level, until you find the appropriate current level (the standard is the same as the measured voltage)
3. Measurement method:
When measuring current with a multimeter current mode, the multimeter should be connected in series in the circuit being tested, as only a series connection can make the current flowing through the multimeter the same as the current in the tested branch. When measuring, the tested branch should be disconnected and the red and black probes of the multimeter should be connected in series between the two disconnected points. Special attention should be paid to not connecting the ammeter in parallel with the tested circuit, as this is very dangerous and can easily cause the multimeter to burn out. At the same time, pay attention to the polarity of the red and black meter rods. The red meter rod should be connected to the current inflow end of the tested circuit, and the black meter rod should be connected to the current outflow end of the tested circuit (the same polarity selection as the DC voltage).
4. Correctly use scales and readings.
When measuring DC current with a multimeter, the dial scale line is the same as when measuring voltage, and it is the second line (with the mA symbol 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, 5A level can be selected. Operation method: Set the conversion switch to the 500mA range, remove the red meter rod from the original "+" socket, and insert it into the socket marked 5A in the lower right corner of the multimeter to measure high currents below 5A.
