How to measure current

Measuring current is an important operation in electronic experiments. In order to accurately measure the current, we usually solve the problem by using an ammeter or a digital multimeter.

When measuring current using a digital multimeter, you first need to set the function of the multimeter to current measurement mode. Then, connect the current input terminal of the multimeter in series to the circuit under test to ensure that the connection is correct. At this time, the value displayed on the multimeter is the current value of the circuit to be measured.

When measuring current, you need to pay attention to the following points: The 1 is to ensure that the function of the multimeter is set correctly to avoid setting the current measurement mode to other modes by mistake; the 2 is to ensure that the connection is correct and avoid connecting the multimeter in parallel in the circuit to cause short circuit; The 3 is to select the appropriate range to avoid damage to the multimeter due to too small range or inaccurate measurement due to too large range.

In some experiments, it may not be allowed or impossible to connect the multimeter in series into the circuit, so it is necessary to use an oscilloscope and a current probe without disconnecting the circuit to be measured. Press the probe handle to open the jaws, put the wire of the measured current into the jaws and release the handle to close the jaws to measure the current in the circuit, which is fast and safe.

In addition, you need to pay attention to avoid applying voltage in the current function when measuring current, otherwise it will cause overcurrent to flow through the measuring instrument and burn the circuit. For safety reasons, some digital multimeters do not even have a current input terminal.