How to test sama ada light cable is normal or not using a multimeter
The general public is first of all the multimeter will be placed in the voltage AC 250V file, check the lamp line of the fire wire and zero line voltage is 220V to determine whether the fire wire and zero line is intact. If the fire wire or zero line open, this method is feasible. However, if the contact is poor into seemingly broken non-broken, it may cause a misjudgement. The reason is that, when the fire wire or zero line there is poor contact inches, due to the multimeter voltage gear resistance, take the circuit current is very small, this current is not enough to produce a large voltage drop in the fire wire or zero line poor contact. Oleh itu, the measured voltage will still be about 220 Ⅴ, once energised with a load of inches, poor contact at the voltage drop will increase ketara, the lamp power supply voltage will be lower than 220 Ⅴ more. There will be lamps and lanterns do not work or not work properly, so the voltage method of measurement, must be energised with a load measurement.
The second method is more reliable, that is, using the resistance method, the multimeter will be placed in the lowest ohm file such as RX1 file, and school zero, and then power off, the switch line and the lamps on the fire wire, zero line dismantled (anti-loop), and then use the multimeter to measure the fire and the zero line, respectively, intact when zero, line contact is poor when there is a resistance, the greater the resistance, the worse the fenomena of poor contact, the resistance to infinity, the line is open.
Use a multimeter to detect the lamp line, there are two kinds: one is a charged measurement, the table will be played to the AC voltage file, the needle was played to the fire and zero line on the direct measurement to see if the voltage is 220 volts, if close to zero volts, indicating that the line has a break point. Dengan the electric pen to measure, if the two strands of the line are red, indicating that the zero line of this strand has been disconnected, carefully check the joints to see if they are loose.
Kedua, power outage measurement. The circuit breaker power off, with a multimeter resistance file to measure the line off, but this method is not very suitable, because the line is long, the needle can not reach, if a separate measurement of the bulb off can also be.
Komprehensif di atas, jelaskan the multimeter to measure the light line, can only use the voltage file to measure the voltage to judge, there are great limitations.
The digital multimeter to AC voltage file, the black pen line in the finger wrapped three to five circles, with a red pen to contact the zero line and fire line, for comparison, read the powder of a large one that is the fire line, the reading of the small one that is the zero line.
