Detailed explanation of measuring current with a digital multimeter
1. Before measuring the current, first determine the nature of the current (AC and DC) and the range of current magnitude.
2. Choose appropriate measurement tools (such as safety, accuracy, and ease of use during on-site measurements) and measurement gears. After selecting the appropriate measurement tool, if you are not a professional technician but just an interested enthusiast, it is recommended to read the instructions for use.
3. General operating steps:
1) If it is a small electrical device (such as an electronic device), you can read the relevant description of the product's electrical power in the product manual. This section sometimes directly indicates the range of current that the electrical device passes through during operation in the manual. If the instruction manual only indicates the power and voltage used, the current can be calculated using the formula "A=W/V". When it is necessary to test the total current of multiple devices in operation, the current of a single device is added to calculate the total current on the main line.
If actual measurement is required:
(1) Select the appropriate gear (measuring current, current value range)
(2) Disconnect the tested line (but the electrical equipment and load cannot be disconnected, otherwise it is a short circuit!), and 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 electrical equipment and load.
2) If it is a relatively large electrical equipment (working voltage generally ranges from 220V to 380V), it is recommended to use a clamp type ammeter (multimeter). The principle is to form a closed electromagnetic field on the energized circuit, and the changes in the electromagnetic field cause the multimeter to generate current. There is a proportional relationship between this current and the measured line current, so that the line current can be directly read in the ammeter.
