How to use a digital multimeter to detect broken points in cables and wires
In addition to measuring basic parameters such as voltage, current, resistance, capacitance, and transistors, digital multimeters can also be flexibly used to further expand their functions and achieve the goal of one meter for multiple purposes.
The method of using a digital multimeter to determine the break point of wires and cables: When there is a break fault inside the cable or cable, due to the wrapping of the external insulation skin,
Make it difficult to determine the exact location of the broken wire. Using a digital multimeter can easily solve this problem. Specific method: Connect one end of a broken wire (cable) to the live wire of a 220V mains power supply, and hang the other end in the air. Turn the digital multimeter to AC2V gear,
Starting from the live wire connection end of the wire (cable), hold the tip of the black probe with one hand, and slowly move the red probe along the insulation of the wire with the other hand. At this time, the voltage displayed on the display screen is approximately 0.445V (measured by a DT890D meter).
When the red probe moves to a certain point, the voltage displayed on the display screen suddenly drops to a few tenths of the original voltage,
The wire (cable) break point is located approximately 15cm forward from this position (the incoming end of the live wire).
When using this method to check the shielding wire, if only the core wire is broken and the shielding layer is not broken, then this method is powerless.
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 place the two probes together, and the reading of the meter should be 0. Next, connect the probes to the top of the line to see what is displayed.
If it is 0, it means it is open, if it is not 0 or if the number is infinite, it means it is open.
Before testing, you can contact the red and black pens of the multimeter to see the number. It must be 0, so if the test wire is connected, it is determined to be 0. Otherwise, if there is a number and the number increases infinitely, it indicates an open circuit.
