Circuit diagram using a single probe to test cable breaks

This article will introduce a circuit diagram that uses a single probe to test whether the cable is broken. Components such as 4060 form a 20kHz oscillator, and the connected 100kfl and 200pF resistor-capacitor components can change this frequency. Each output of the IC, such as Q3 and Q4, can drive a light-emitting diode or a piezoelectric buzzer to provide necessary indications. This circuit is installed in a metal box. Hold the cable with one hand and the tester with the other hand, and touch each pin of the cable with the probe in sequence. If the pin is connected, stray capacitance will reduce the tone frequency. Perform the same test on the other end of the cable. The break should be at the end where the frequency is least affected by stray capacitance. Touch one pin of the cable with the probe and hold the other end of the cable with your other hand to check one-on-one. If the cable is intact, the oscillator will stop oscillating. Short circuits in the internal coils of motors and large inductors can also be checked by comparing them with each other. A single probe tests the multipath for pass, break and indicates which end is broken, as shown below.