Cable breakage measuring instrument circuit

This device uses a single probe to test whether multiple paths are connected or disconnected and indicates which
end is broken, as shown in Figure 5-25.
    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 of the frequency that 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.