How to Measure a Cable Break Using a Digital Multimeter
How a Digital Multimeter Measures a Cable Break
The method of judging the breakpoint of the wire and cable with a digital multimeter: When the cable or cable has a broken line inside, due to the wrapping of the outer insulation,
Make it difficult to determine the exact location of the broken wire. This problem can be easily solved with a digital multimeter. Specific method: Connect one end of the wire (cable) with a breakpoint to the live wire of the 220V mains, and the other end is suspended in the air. Pull the digital multimeter to AC2V gear,
Starting from the live wire access end of the wire (cable), hold the nib 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 about 0.445 About V (measured by the DT890D meter).
When the red test pen moves to a certain place, 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 where the breakpoint of the wire (cable) is.
When using this method to check the shielded wire, if only the core wire is broken but the shielding layer is not broken, then this method is powerless.
How to use a digital multimeter to detect wire breakage
1. First of all, prepare the digital multimeter for use, and use the multimeter to easily measure whether a wire is on or off.
2. Then put a wire on the table.
3. Insert the red plug of the multimeter into the rightmost socket, and insert the black plug into the COM socket.
4. Then turn the middle knob to the small horn.
5. Then let the metal touch the two ends of the bare metal wire of the wire. If there is a sound and the value changes, it means that the wire is ok.
6. If there is no sound and no change, the value display 1 means the wire is broken and the resistance is infinite.
7. The power cord in use needs to be turned off. Disassemble the two ends of the wire, and then turn the multimeter to resistance*100. Then use the two positive and negative test rods of the meter to connect the two ends of the tested wire to test whether there is a breakpoint.
8. If you want to test a disconnected but connected wire, it cannot be tested.
How to test the continuity of a wire with a digital multimeter
Turn the selection 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, and then connect the test leads to the first position of the line to see what is displayed.
If it is 0, it means on, if it is not 0 or the number is infinity, it means off.
Before the test, you can touch the red pen and the black pen of the multimeter to see the number. It must be 0. If the test wire is connected, it will be 0 decisively. Otherwise, if there is a number, and the number increases infinitely, it means an open circuit.
