Network cable tester

With two cheap integrated circuits and a few parts from the ‘junkbox’, this very simple and useful circuit, can be put together in just a few hours.
This cable tester, tests all the 8 wires in a network cable in one move, if one of the 8 LEDs does not lit up, it means that the wire corresponding to that LED is faulty.

You need:

  • 1 x 4017 decade counter,
  • 1 x 555 timer,
  • 8 x LEDs,
  • 2 x 8P8C modular connector (RJ45),
  • 8 x 100Ω resistor,
  • 1 x 10KΩ resistor,
  • 1 x 15KΩ resistor,
  • 1 x 4,7µF capacitor.

network-tester

IMG_20150517_173252

IMG_20150517_173313

The yellow LED has no special significance, I only had 7 green LEDs.

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