Multi-Wire Cable Tester

In a general way, the Cable Tester is the device by which we can check whether the cable has defected or it is connected in a proper way. A cable tester is the very useful way to determine the physical quality or connectivity of the cable or wires individually while installing them. It detects whether the cable is connected properly and the communicative strength between the ends of the cable. Some advanced cable tester tests the signal transmission properties like resistance, noise, interference etc. Some of the cable testers available in the market are LAN, CAT 5, CAT 6, CAT 7.

In this circuit, we are showing the Multi-Wire Cable Tester by which we can check that the wire or a cable whether it is defective or not.



  • 555 Timer IC
  • 4017 IC
  • Resistors (10k-1, 2.2 k-2,500 k-4,)
  • Capacitors (10uf-1,10nf-1)
  • Red LED
  • 9V supply
  • Jumper Wires
  • Bread Board



Multi-Wire Cable Tester circuit diagram

Multi-Wire Cable Tester circuit hardware



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Here in this Cable Tester Project we have fed 4017’s clock input with 555 timer astable output and connected the four wires to be tested to the four outputs (Q0-Q4) of the 4017. Four LEDs are also connected to those four wires, which indicate whether wires are working or defective. If all the four wires are fine then all the four LEDs will be blinking continuously and if any of the wire breaks then respective LED will stop blinking


Working of Cable Tester

In this circuit, we are using 555 Timer IC in astable mode to generate a clock signal. The frequency of Clock pulse is dependent on resistance R1=2.2 KΩ, R2=10 KΩ, and capacitor C1=10µF. For finding the value of these components you can use the 555 timer frequency calculator to generate the required frequency. The speed of blinking LEDs will depend upon this Frequency.

Multi-Wire Cable Tester

The clock pulse through the 555timer IC feeds to the pin 14 of a 4017 decade counter IC.As we are using only four outputs of this IC so we have connected the 5th output to the reset pin to reset the IC. So that as soon as the 5th output Q4 is high, it resets the IC and makes the Q0 high again.

We have used four wires to demonstrate 4 wire Cable Tester. If the wires are not defective then it allows the current to conduct through them and feed to the LED and the LED goes HIGH. If there is any fault, break in the wire the LED will not glow. By which we will get to know that there is some defect in the wire. Here, the test is complete we get the result of wire that whether it is defective or not. So if all the four wires are fine then all the four LEDs will be blinking continuously and if any of the wire breaks then respective LED will stop blinking.

Check the demonstration Video given below to understand the concept.


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