In addition to the measurement of basic parameters such as voltage, current, resistance, capacitance, and transistor, the digital multimeter can also be used to further expand its function and achieve the purpose of multi-use. The method of judging the break point of wire and cable with a digital multimeter is now given. When the cable or the inside of the cable breaks, the exact location of the disconnection is not easy to determine due to the outer insulation wrap. A digital multimeter can easily solve this problem. Specific method: Connect one end of the wire (cable) with a breakpoint to the live line of 220V mains, and the other end is suspended. Pull the digital multimeter to the AC2V block, starting from the live end of the wire (cable), hold the nib of the black test pen with one hand, and slowly move the red test pen along the insulation of the wire with the other hand. The voltage value displayed on the screen is about 0.445V. When the red test pen moves to a certain place, the voltage displayed on the display suddenly drops to 0.0 a few volts (about one-tenth of the original voltage), and about 15cm forward from this position (the live wire access end) is the wire ( Cable) where the breakpoint is. When using this method to check the shielded wire, if only the core wire is broken and the shielding layer is not broken, this method is powerless