Multi-core cable breakage detector circuit

Shown is a multi-core cable breakage detector circuit. This circuit can check multiple wires at the same time to quickly and accurately detect
whether and which wire is broken in the cable
- especially suitable for telecommunications maintenance personnel.
    The circuit is mainly composed of a self-excited oscillator (composed of a capacitor
cl, a resistor and transistors VTI and
VT2), a pulse distributor CD4017 and
an indication circuit . When in use, one end of the cable to be tested should
be grounded, and the multi-strand wire ends at the other end should be connected to the YO~Y9 output terminals of the detector
respectively . After the pulse signal output by the self-oscillator is processed by CD4017, a high level is output from its YO-Y9 to provide operating voltage for the light-emitting diode. When the wire under test is intact, the positive and negative electrodes of the light-emitting diodes are at the same potential ( the resistance of the cable is very small), and LED1 to LED10 do not light up. If a wire is broken, one end of the light-emitting diode will be The current resistor is connected to high potential and the other end is connected to ground, so the corresponding light-emitting diode is lit, so that all the wires can be inspected quickly.