A multimeter showing a short-circuit in the measuring lead shows a resistance value what is it?
Here's the situation, I've encountered it many times:
Before the circuit is first powered up, I use a multimeter in the on/off position to measure the circuit for shorts before closing the circuit. This time are normal, the multimeter does not beep, also shows infinity.
After a few months of use, routine maintenance, with the multimeter through the short-circuit measurement, the pen on the two lines that will beep for a moment, and then there is no sound, the multimeter screen shows more than 60 to 80 resistance.
So can not figure out whether this is a short circuit or not, and the gate can be closed, it feels inexplicable.
1, at the beginning of the two lines have no resistance, when used for a period of time and then come back to review, turn off the fire zero line actually have resistance, and the buzzer horn is also called, in the usual practice, I see this situation, the judgement is as follows:
2, the known conditions are indoor installation and commissioning after handing over the use of households between the line of no-load resistance, how the user used for a period of time after the line with the line of no-load resistance? Is this a wire leakage? This phenomenon is the country's official electrician is the most sensitive issue, his first reaction is to use the shaking table, no megohmmeter can not find out the problem. This phenomenon is also like the old doctor and young doctors, old doctors listen to the complaints will know what disease, young doctors is to rely on the instrument.
3, I often use energy-saving lamps on the 400V electrodeless capacitor as a resistor, the old fluorescent lamps on the neon tube to take down the glow by a series when the indicator, because this form of indicator in the mobile socket have seen. An electrodeless capacitor has a characteristic, can store a certain charge, if you pass the electricity, do not pay attention to a touch on the human hand with electric induction.
4, double-check the amount of resistance, only two reflections, and then there is no more, that is, I cited this example above.
5, when the user's wall socket has a mobile socket, this mobile socket has a switch and indicator, after closing the main power supply, this mobile socket is not unplugged, (my experience, the article about electricity are prompted to dial all plugs and indicators) is that this indicator is caused by the fire and zero wire is connected.
