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mini review.

Discussion in 'Lighting' started by Clive Mitchell, Sep 22, 2005.

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  1. I just got one of the 32 LED UV torches from ebay. It works well and
    projects a very concentrated beam of near UV light. As with many of
    these torches it just dumps the huge parallel array of LEDs directly
    across a pack of three measly AAA cells. This means that LED current
    will vary according to battery quality, type and life.

    The LEDs also have distinctly different intensities suggesting poor
    forward voltage matching.

    Other than that it's a lot of fun. Just walking about your house at
    night with it on reveals some unusual fluorescing objects.

    The case is the usual classy machined aluminium and is chunky and nice
    with a proper on-off push button.
     
  2. JohnR66

    JohnR66 Guest

    What did you end up paying? How does it compare to a black light?
    John
     
  3. The cost is in the "postage" but I bid for about 2.5UKP.

    The beam of UV is actually very good. It would make a good UV
    spotlight.
     
  4. Nope. The current is limited by the battery impedance, the torch
    metalwork and the PCB tracks, so there's not much limiting there.

    Some of the ebay torches with small numbers of LEDs do use resistors,
    but the big torches don't. I think this includes the torches with the
    counterfeit Luxeons in them.
     
  5. They do that single AA style torch in a wide number of LEDs. I think
    the biggest uses 12 LEDs.
     
  6. The Chinese torches that I've opened tend to use a little two transistor
    booster with a small choke. A bit like the circuit in many solar
    lights.
     
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