How to measure DC current with a multimeter, four steps to keep in mind
The multimeter has many uses. Here is the method of measuring DC current with a multimeter. It is divided into four steps. If you want to protect the accuracy of the result of the multimeter measuring DC current, you must strictly follow the measurement steps. Keep in mind the four steps. Measuring DC current is easy.
1. Mechanical zero adjustment
The multimeter can measure resistance and voltage, and the multimeter should be mechanically zeroed before use.
The mechanical zero adjustment method is the same as the mechanical zero adjustment operation for measuring resistance and voltage. Generally speaking, the mechanical zero adjustment operation of the multimeter, if it is a multimeter that is often used, does not need to be mechanically zeroed every time.
The method of mechanical zero adjustment: Separate the two test leads, and use a flat-shaped screwdriver of appropriate size to adjust the mechanical zero adjustment screw located in the middle of the dial until the pointer coincides with the zero scale line.
2. Select the range
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, first use the highest current gear (500mA gear) to measure, and gradually switch to the lower current gear until you find a suitable current gear (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 current of the branch 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.
Note that the ammeter cannot be connected in parallel in the circuit under test, this is very dangerous, and it is very easy to burn 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. Scale and reading
Correct use of scales and counts: When the multimeter measures DC current, select the scale line on the dial, which is the same as when measuring voltage, and it is the second track (the right side of the second scale line has the mA symbol). 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.
