How to measure current with a multimeter? How can a multimeter be used to measure current?
When measuring direct current (DC) current, place one of the multimeter's conversion switches in the DC current position, and the other conversion switch on an appropriate range from 50μA to 500mA. The method of selecting the current range and reading the value is the same as that for measuring voltage. During the measurement, the circuit must be disconnected first. Then, according to the direction of current flowing from "+" to "-", connect the multimeter in series to the circuit under test, that is, the current flows in through the red test lead and out through the black test lead. If the multimeter is mistakenly connected in parallel with the load, due to the very small internal resistance of the meter head, it will cause a short circuit and burn out the instrument. The reading method is as follows: the actual value = the indicated value × the range / the full-scale deflection value.
Precautions for Measuring Current with a Multimeter
When measuring current and voltage, do not change the range while the circuit is live.
When selecting the range, choose the larger one first and then the smaller one. Try to make the measured value close to the selected range.
When measuring resistance, do not measure while the circuit is live. Because when measuring resistance, the multimeter is powered by an internal battery. If measuring while live, it is equivalent to connecting an additional power source, which may damage the meter head.
After use, set the conversion switch to the maximum AC voltage position or the neutral position.
Note that when changing the range of the ohmmeter, it is necessary to perform ohmic zero adjustment, and there is no need for mechanical zero adjustment.
There are two ways to measure current using a digital multimeter. The first method is to directly measure the current with a digital multimeter. It is necessary to connect the multimeter in series with the circuit under test, which means disconnecting the circuit and using the test leads of the digital multimeter to form a complete circuit. In this way, all the circuit current flows through the circuit of the digital multimeter.
Another indirect method of measuring current with a digital multimeter is to use a multimeter accessory, namely a current probe. Clip the probe outside the conductor, so there is no need to disconnect the circuit, and it is possible to measure large currents greater than 10A.
