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  1. K

    Contact Resistance Tester

    Hi Hero I did think about the resistance of the wires and thought about using the Kelvin 4 wire method to reduce the effects of the wiring. My preferred method of reading the measurement would be using a microcontroller as it would probably be more accurate and wouldn't require calibration...
  2. K

    Contact Resistance Tester

    Hi Hero Thanks also for replying to my query. I did think of using a constant current source but wasn't too sure how to go about it. You mentioned measuring resistances higher than 100m ohms and using an amplifier I can see where you are coming from. When you mention the panel meter would this...
  3. K

    Contact Resistance Tester

    Alex Thanks for replying. This project is for professional use. I work in the rail industry which uses 50V d.c. relays for operating safety critical circuits. Because of the safety involved then there is a lot of proving i.e. once a relay is energised/de-energised a 50V d.c. supply is then fed...
  4. K

    Help needed for Project - Train Traffic Control...

    Hi there Could you provide me with more details as to what the project is for i.e. a real rail network or simulation? What type of relays does the interlocking use and would you be looking to perform commands to the interlocking or purely operate off indications, Cheers Killeavy
  5. K

    Contact Resistance Tester

    Hi I'm new to this site and I'm looking to design an item of test equipment which will be able to measure contact resistance of relays and then display them on an LCD display. The values of resistance i would be looking at are in the region 100m ohms to approx 20 ohms. Above 20 ohms doesn't...
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