Digital multimeter measuring current method and usage of current gear
Current measurement is not the same as measuring other quantities with a DMM. The direct current measurement method is to connect the digital multimeter directly to the circuit under test, so that the current of the circuit under test flows directly into the internal circuit of the multimeter.
The indirect measurement method does not require opening the circuit and stringing the multimeter to the circuit under test.
The indirect method uses a current clamp.
First of all, the multimeter must have a current-measuring gear.
Then, insert the test leads into the current-measuring jack on the left, and then string the multimeter into the line to be tested.
If you don't know how much current there is, it is best to adjust the gear to a higher gear, and if it is not suitable to lower it by one gear, so as not to burn the watch.
①Insert the red test lead into the "μ, mA, ℃" or lOA jack, and the black test lead into the "COM" jack.
②Set the function range switch to μA￣=, mA￣ or A current measurement gear. The default setting is DC current measurement. To perform AC measurement, press SE-LECT blue key to select AC current measurement.
③ When measuring current, the test leads should be connected in series in the circuit under test, and the red test lead should be close to the positive side of the power supply, otherwise "-" will appear in the LCD display (the AC current test lead is not divided into positive and negative).
④Read the measurement result from the LCD display, the value measured by U and OE is the true effective value.
Measurement Notes:
①The correct jack, function file and range should be used when measuring. If the magnitude of the current cannot be estimated, the test should be started from a high range;
②When testing high current, for safety reasons, each measurement time should be less than 10S, and the interval time should be greater than 15min;
③When the test lead is inserted into the current jack, do not connect the test lead to any circuit in parallel, otherwise it may blow the fuse or even the multimeter itself.
