Why does a multimeter show a resistance value when measuring a short circuit on a circuit?
1. At first, there was no resistance between the two wires. However, when rechecked after using them for a period of time, there was resistance when the fire neutral wire was turned off, and the buzzer sounded. In my daily practice, I have seen this situation and my judgment is as follows:
2. The known condition is that there is no resistance between the wires when the indoor installation and debugging are handed over to the user for use. How did the user experience resistance between the wires when they are unloaded after using for a period of time? Is this a wire leakage? This phenomenon is the most sensitive issue for national electricians, and their first reaction is to use a megohmmeter. Without a megohmmeter, the problem cannot be detected. This phenomenon is similar to that of old doctors and young doctors. Old doctors know what disease they have when they hear a chief complaint, while young doctors rely on instruments.
3. I often use the 400V infinite capacitor on energy-saving lamps as a resistor, and take off the neon tube starter on old fluorescent lamps and connect it in series as an indicator light, because this type of indicator light has been seen in mobile sockets. The characteristic of an infinite capacitor is that it can store a certain amount of charge. If you use electricity and accidentally touch it, there will be an electrical induction on your hand.
4. When retesting the resistance value, there were only two reflections, and it disappeared afterwards, as in the example I mentioned above.
5. When there is a mobile socket on the user's wall socket, there is a switch and indicator light on the mobile socket. After turning off the main power, the mobile socket is not unplugged (based on my experience, articles related to electricity all suggest unplugging all plugs and indicator lights). This is because the indicator light causes the fire neutral wire to be connected.
I don't know the specifications, length, and installation environment of the wire. The new wire has no sound or resistance, which indicates that it is normal. After use, the electrical interference between the wires can easily cause interference to the digital multimeter due to the power on of the wire. It is recommended to short-circuit the tested wire before testing, or use a shaking table for more accurate testing.
