How to measure short circuit and open circuit with multimeter after tripping
The multimeter is an essential tool in the maintenance of our weak current lines. Let me briefly introduce how to test the short circuit, open circuit and leakage of the line.
Multimeter short circuit
First, insert the black test lead of the multimeter into the "com" hole, insert the red test lead into the "V Ω" hole, and turn the knob to the buzzer position. Disconnect the power supply of the tested circuit, and test the two wires of the circuit with two test leads. If the resistance of the multimeter shows 0 and there is a beep, it means that there is a short circuit in the circuit. You can also use the ohm 1k or 10k range, disconnect the other end of the line, and test the two lines with two test leads. If the resistance of the multimeter shows 0, it means that there is a short circuit in the line.
multimeter open circuit
When we are testing the continuity of the line, we must disconnect the power before testing. Turn the knob switch to the buzzer position, and test that the two ends of the line are in contact with the metal needles of the test pen. If there is a certain resistance and there is a buzzing sound, it means that the line is connected; if the resistance is infinite, it will be displayed as 1. And there is no beep, the line is disconnected. Or select the 10k range of the multimeter, short-circuit the other end of the line, and test the two lines with the test leads of the multimeter. If the resistance of the multimeter shows 1, it means an open circuit; if it shows 0, the line may be connected.
How to repair the meter line and test lead falling off of the multimeter
1. The red and black pen of the multimeter is on the stake, which can be pulled out at will. I saw a metal male socket connected to a leather wire. Because the wiring point of this wire post is easy to break, I tell you that the wire of my test pen is much shorter. , I have repaired it many times, and I waste 1 centimeter each time. I have repaired both types of watches (electronics and pointers). , clamp the metal stake on the vise, melt the solder wire with a soldering iron, and then strip off the leather wire by half a centimeter to expose the copper wire, and melt it with tin. It is best to put an insulating wax tube on the wire, so that after welding, the outside It is not easy to break with the casing.
2. The wire post of the digital meter is not easy to weld, its plastic sleeve is big and hard, you have to pull it out first and put the wire in, and then return it to its original position after welding on the outside, if you do not even have welding skills No, it would be difficult!
Look at the top of the red pen stub is the plastic sleeve that was repaired and then ironed the crack with a soldering iron.
People who can own and use multimeters will have a certain understanding of radio and electrical appliances and contact maintenance. They must use electric soldering irons, and soldering can be used to disassemble them.
