Polarity tester for cables

Discussion in 'General Electronics Chat' started by Stevepearce, Feb 20, 2012.

  1. Stevepearce

    Thread Starter New Member

    Feb 20, 2012
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    Hi everyone I am trying to make a cable polarity tester the cable has 9 cores. I thought I had crack it using a 9volt bat some LEDs and resistors but all I made was a continuity tester. Help.
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Somrthing is missing, 'do not connect with cables having polarity, unless a voltage of a given polarity is applied. With your continuity detector, if you connected two diodes [ anode & cathode to cable ] in series with existing resistors & LEDs, then you could tell polarity of applied V.
     
  3. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    You can use a loopback plug and a 4017 counter to light 8 LEDs in sequence from a known common ground, you'd only need some basic electronic circuit and Bi-Color LEDs with a resistor, see Bill Mardsen's Blog page for sequencer schematics.

    That is the way cheap Cat5 cable "certifiers" work, Just a DC to make sure all the pins are in the right order for both ends of the connector.

    If you are working on a "Hot" circuit, and not a patch cable, then discard all info above and please provide as much information as possible regarding voltage, current connector type, etc. A solution in that case would be a ring Hall Sensor around each wire, when the output is positive, the current is going with the arrow on the little snap on connector, if it is negative, it is going the opposite way (or AC Voltage)
     
  4. Stevepearce

    Thread Starter New Member

    Feb 20, 2012
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    Sorry chaps I should of explained better I have two connectors on my cable one female one male what I need to test is the wire 1 male end goes to wire 1female end and so on for all 9 positions. I have been using a DMM but need to make a test jig now. Thanks
     
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Might use a sequencer, 4017, as suggested by thatoneguy, to feed a pulse to #1-M, & to a 2 in and gate, other input goes to #1-F socket. If continuity is achieved, and gate out drives a green LED. A second and gate can be used to indicate a failed test & maybe stop sequence. A good test could feed an 8 in OR & used as a clock. If all connections were good, the test would be completed before you could blink an eye. If interested, I or We might scratch up something.
     
    Last edited: Feb 22, 2012
  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Here is a sketch of a sequencer, self clocking once started. Only one of 9 channels is shown. A seprate clock , or manual clock could be used to slow down operation. Atleast something to think about.
     
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