ethod of measuring current with digital multimeter and operation steps of multimeter
Regarding the method of measuring current with digital multimeter, preparations before measuring current, judging the nature of current, current size range, operation steps when measuring current with digital multimeter, etc.
How to measure current with digital multimeter
1. Before measuring the current, first judge the nature of the current (AC and DC) and the current size range.
2. Select the appropriate measurement tools (such as safety, accuracy and ease of use during on-site measurement) and measurement gears. After selecting the appropriate measuring tool, if you are not a professional technician, but just a hobbyist, it is recommended to read the instructions for use.
3. General operation steps:
1) If it is a small electrical equipment (such as electronic equipment, etc.), you can read the relevant description of the electrical power of the product in the product manual. This part of the description sometimes directly indicates the current range of the electrical equipment when it is working. In the manual.
If the instructions only indicate the power consumption and voltage, the current can be calculated by the formula "A=W/V".
When it is necessary to test the total current when multiple devices are working, add the currents of the individual devices to calculate the total current on the main line.
Actual measurement:
1) Select the appropriate gear (measure current, current value range)
2) Disconnect the line under test (but the electrical equipment and the load cannot be disconnected, otherwise the line is short-circuited!), insert the multimeter into the line (note that it is connected in series), at this time the resistance of the multimeter is almost zero, and the current flowing through the multimeter is Equal to the current flowing through the consumer and the load.
2) If it is a larger electrical equipment (working voltage is generally 220V to 380V), it is recommended to use a clamp ammeter (multimeter). The principle is to form a closed electromagnetic field on the power line, and the change of the electromagnetic field causes the multimeter to generate current. This current is proportional to the line current under test, so that the line current can be read directly in the ammeter.
