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mini christmas lights

Discussion in 'LEDs and Optoelectronics' started by KTW, Dec 19, 2015.

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  1. KTW

    KTW

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    Feb 22, 2015
    I have a set of 2.5 volt tree lights with a few bulbs burnt out.
    I have replaced several and have some working but some refuse to co-operate.
    The sockets have been tested at 2.2 volts, the bulbs will light when 2.4 volts is supplied directly to them and when I connect the bulb leads directly to the contacts inside the socket it will light the other lights in the string but it won't light the bulb itself.

    http://ecx.images-amazon.com/images/I/41Z3M4RAQAL._AC_UL320_SR292,320_.jpg
     
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    Perhaps you have a fault in the socket. Inserting the bulb may be causing a short-circuit across the socket.
     
  3. KTW

    KTW

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    Feb 22, 2015
    Thanks for the response Alec.
    I'm convinced it's the bulbs.
    I can take a working bulb and put it in a socket where the bulb doesn't work and it lights.
     
  4. BobK

    BobK

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    Jan 5, 2010
    It sounds like the replacement bulbs want more current than the originals. It could pass a small current without lighting. Can you test and original bulb and the replacement for current draw at 2.4V?

    Bob
     
  5. JWHassler

    JWHassler

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    Dec 22, 2014
    Consider how those serie-string lights work
     
  6. KTW

    KTW

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    Feb 22, 2015
    The voltage for the original string is 2.5 volts and the replacement bulbs are 3.5 volts.
    What was confusing was the 3.5 volt bulbs were operating on there own with 2.5 volts but when put in with the rest of the string some would work and some wouldn't.
    I'll make sure the replacement bulbs are .5 watt and 2.5 volts.
     
  7. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    That is strange. I would expect the 3.5v bulbs to just burn dimmer than the rest.
     
  8. gorgon

    gorgon

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    Jun 6, 2011
    You didn't say the wattage of the 3.5V bulbs, if it's much higher than the other bulbs you may have your answer.
     
  9. KTW

    KTW

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    Feb 22, 2015
  10. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    And the wattage will be different if running at other than the proper voltage.
     
  11. KTW

    KTW

    273
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    Feb 22, 2015
    Wife brought home the proper bulbs today and everything is good, thanks for the replies.
     
    Tha fios agaibh likes this.
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