Research on the specific application of digital multimeter in testing automobile circuits
3.1 Measurement of AC and DC voltages in automotive circuits
Digital multimeters can measure AC voltage and DC voltage in the measurement of automobile circuits, but the correct voltage value must be measured under the established measurement procedures.
First of all, the range and range of the digital multimeter should be placed in the area of the voltage range, and at the same time, the most
Large measuring range. Insert the red pen of the digital multimeter into the red jack with the voltage symbol, so that it can be prepared for the correct measurement in the later stage. The black test lead should be inserted into the COM jack of the digital multimeter, and the specific content is shown in Figure 1 below [2].
figure 1
Secondly, in the battery with sufficient power supply, verify whether the voltage range of the digital multimeter is in normal working condition. Then connect the black test lead of the digital multimeter just inserted to the negative pole of the battery with sufficient power, and the red test lead to the positive pole of the battery. After the connection is successful, when the voltage value of the digital multimeter is displayed as 12V, it means that the digital multimeter is The voltage file function is normal. When measuring the voltage of the circuit, similar to just now, use two black and red test leads to connect to the two stages of the circuit respectively. When the voltage value is actually two or three decimal places below 0, it represents the voltage range Bit range selection is too large. At this time, the two test leads of the digital multimeter should be disconnected from the power to be measured, and the voltage between the circuits should be continuously measured after switching the voltage gear to a lower range. The measured voltage is the result of the circuit. The correct voltage value [3]. During the above measurement process, if there is an error in the positive and negative poles of the line connecting the red test lead and the black test lead, it will not affect the measurement result, nor will it damage the function of the digital multimeter.
