AC Home Circuit Tester

Discussion in 'General Electronics Chat' started by Tommy Ketchup, Aug 1, 2008.

  1. Tommy Ketchup

    Thread Starter New Member

    Aug 1, 2008
    3
    0
    Hi Everyone!!

    I hope you are all well and keeping out of trouble!!!

    So I have made a super simple Home AC plug tester for my RV with 2 leds and resisters, one LED lights up to indicate power and the other lights up to indicate if the Phase and Neutral wires have been switched.
    It works great but I would really like to start experimenting with dual color LEDs and make up a circuit which would work for this.
    The thing is I dont have a clue about all these different LED types, there's dual color 3 pin, bi polar 2 pin.... and so on???

    Would someone be able to help me out with a little info on how i could do this?? :)

    Thanks very much :D
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    What resistor values did you use, and did you put a diode opposite to keep the back voltage from exceeding the PIV of the LED?
     
  3. Tommy Ketchup

    Thread Starter New Member

    Aug 1, 2008
    3
    0
    Hey Bill,

    I used a 120K resistor on the live to neutral and then a 25k resistor from neutral to earth. both are running 3mm 20ma LEd's.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Using a dual colour led with two pins is not a good idea, the circuit gets complicated. I suggest you to use the dual colour leds with three pins. its the same as using two leds but you use the one of the three pins as a common pin. Then each of the rest of the pins is used for each colour.
     
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Voltages and electrical standards in Ireland are very similar to those in the UK.

    It is both illegal and downright dangerous to allow mains voltages to be as close as the leads of a multicolour LED.

    Use separate LEDS for each function. This is still cheaper than multicolour.

    Why are you not using the traditional three lights as you cannot indicate all possible fault conditions with only two?
     
  6. Tommy Ketchup

    Thread Starter New Member

    Aug 1, 2008
    3
    0
    I have wired these two LED's into the casing of my plug so I know when i have power and if the live and neutral are wired correctly at a glance. I was a little hesitant of wiring a LED and resistor from Live to Ground for continuous use as it will then be giving a feed to ground. My thinking of this is that it may start tripping the breaker on the GFCI??? Does that sound right???
     
  7. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    I assume this is a portable socket tester; these circuits are not meant to be permanently in place.

    All mine came from the days when neons were used, rather than LEDs. I think the Martindale brand are still available. Maplin used to have one for a couple of pounds but I can't find it at the moment. I even made one of my own set into a standard 13amp plug. Remember to blank off the cable entry if you do this.

    As did CPC-Farnell. Here is the link to their commercial LED offerings, which are more expensive.

    http://cpc.farnell.com/jsp/search/b...tk=gensearch_003&Ntt=mains+socket+tester&Ntx=

    Tripping? Shouldn't do, the breaker should be rated at 30mA. Keep the curent below this.

    I keep one in my toolbox - it's amazing how many problems I find going around strange premises all the time. This is for my own safety and peace of mind as I'm not an electrical contractor. I repair computers and other electronic equipment and find that every so often a failure can be traced to a mains wiring fault.
     
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