2.1 Measuring the internal resistance of the component
In the manual of Boeing aircraft, the determined resistance value of each component will be given, so if you want to know whether the resistance value of each component is normal, directly disconnect the electrical plug of the relevant component and use the ohmmeter of the digital multimeter.
The file can measure the resistance value.
2. 2 Line continuity measurement
Since the lines on the aircraft are relatively long, the way to measure the path of the line is to disconnect the components at both ends of the line, then connect one end to the ground wire of the aircraft, and measure the resistance of the other end to the ground. The measurement path is completed using the ohm range of the digital multimeter. Considering the existence of contact resistance, if the measured value is stable within a few ohms, it means that the line is intact; if the resistance value is large, it means that there is an open circuit somewhere in the line. You can also use the "short circuit test function" of the digital multimeter to prove that the line is connected when the buzzer beeps.
2. 3 Component power supply measurement
If you want to judge whether the power supply of the component is normal, you must first find out in the manual whether the power supply type of the component is DC or AC, as well as the value of the power supply voltage, and then disconnect the power plug of the component and close it.
Close the trip switch, use the DC voltage file or AC voltage file corresponding to the digital multimeter to measure. In aircraft, components are typically supplied with either 28V DC or 115V AC. When measuring 115V AC voltage, pay attention to safety due to the high voltage.
3 Conclusion
Digital multimeter is one of the electronic measuring instruments commonly used in aircraft electrical and electronic system troubleshooting. Familiar with the function, structure, use method and precautions of the digital multimeter, whether it can be used in aviation maintenance
It is very important to judge the fault point accurately and quickly. With the development of science and technology, digital multimeters will play a greater role in aviation maintenance.
