Using a digital multimeter to measure cable breaks
How to use a digital multimeter to determine the breakpoint of wires and cables: When a breakage fault occurs in a cable or cable, due to the outer insulation wrapping,
The exact location of the broken wire is difficult to determine. This problem can be solved easily with a digital multimeter. Specific method: Connect one end of the wire (cable) with a breakpoint to the live line of the 220V mains power, and leave the other end floating. Pull the digital multimeter to AC2V.
Starting from the live wire access end of the wire (cable), hold the tip of the black test lead with one hand, and slowly move the red test lead along the insulation of the wire with the other hand. At this time, the voltage value displayed on the display is approximately 0.445 V (measured by DT890D meter) is about.
When the red test lead moves somewhere, the voltage displayed on the display suddenly drops to 0.0 volts (about one-tenth of the original voltage).
About 15cm forward from this position (live wire access end) is the break point of the wire (cable).
When using this method to check the shielded wire, if only the core wire is broken but the shielding layer is not broken, this method is powerless.
How to use a digital multimeter to detect broken wires
1. First, prepare the digital multimeter for use. The multimeter can easily measure whether a wire is connected or broken.
2. Then place a wire on the table.
3. Insert the red plug of the multimeter into the rightmost socket and the black plug into the COM socket.
4. Then twist the middle knob to the small speaker.
5. Then let the metal touch both ends of the exposed metal wire of the wire. If there is a sound and a change in value, it means that the wire is OK.
6. If there is no sound or change, the value showing 1 means the wire is broken and the resistance is infinite.
How to use a multimeter to test for broken wires
1. The power cord needs to be turned off when in use. Disconnect both ends of the wire, and then turn the multimeter to the resistance*100 setting. Then use the two positive and negative test rods of the meter to connect the two ends of the wire under test to detect whether there is a break point.
2. If you want to test the wire that has been disconnected but connected back, it will not be measured.
How to test the continuity of a wire with a digital multimeter
Turn the selector knob of the digital multimeter to the ohm position, which is the R position.
Then put the two test leads together. The reading of the meter should be 0. Then connect the test leads to the first position of the line to see what the display is.
If it is 0, it means open, if it is not 0 or the number is infinity, it means open.
Before testing, you can touch the red pen and black pen of the multimeter to see the number. It must be 0. If the test wire is connected, it must be 0. Otherwise, there is a number, and if the number increases infinitely, it means an open circuit.
