Mains tester screwdriver

Discussion in 'General Electronics Chat' started by Steve1992, Nov 1, 2008.

  1. Steve1992

    Thread Starter Senior Member

    Apr 7, 2006
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    What are the physics that make this piece of test equipment work?

    Thanks.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    I think it's no more than a current limiting resistor and a neon lamp.
     
  3. mik3

    Senior Member

    Feb 4, 2008
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    Its just a high resistance resistor in series with a neon lamp. When you touch the bit of the screwdriver on the hot (live) wire current passes through the resistor, the neon lamp and your body down to ground and the neon lamp illuminates. You dont get shocked by the current because its very small. Because the current increases with voltage if you exceed the voltage rating of the device, its written on it, you will get shocked.
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    We had a buried conduit with two exposed ends,no identification in breaker panel , hot or cold and not a meter around except for my trusty pocket screwdriver. It was still HOT. I still have most of a working driver.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    You should see the notch in my wire stripper that came from cutting a pair of live wires. Sure do believe in insulated handles.
     
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