OT: AC to DC transformer source needed

Thanks all. I just assumed that since the label on the light listed the output voltage as: 12v dc 1.7A, that I needed a DC output. The
bulb is a bi-pin capsule bulb that costs $17 from the light maker - I bought one just so that I could try to read the fine print on the bulb so that in the future I could source on thru McMaster or Grainger.
One of the first places that I looked for a transformer was in a woodworking supply catalog - specifically for the low voltage lights found in some cabinetry. In my online surfing, I found numerous 12v AC transformers that were in ther right amp range and also cheap - just did not realize I could use one of them.
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    A warning which may not have been included with the packaging for that bulb -- Handle it with clean cloth, or gloves. The natural oils from fingers will etch the quartz envelope of the bulb in the presence of the strong ultraviolet from that filament. It probably came with some kind of sleeve to protect it while you install it.
    If you have already handled it -- clean it with alcohol or acetone before putting it into service. I don't know for sure, but I suspect that the bulb's failure mode from this would be to shatter while warming up or cooling off sometime downstream, after the etching has gotten deep enough.

    Yep -- you can.
    Good Luck,         DoN.
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This is really good advice. But I would suggest even one step further, which is clean *all* quartz halogen lamps before putting them in to service, if the owner has touched them or not.
I went through a fair number of them rapidly at work, before realizing that the failed ones had fingerprints on them - and I was wearing gloves when they were installed! The failure mode was not terribly dramatic, the gas in the envelope gets contaminated and the interior is darkened and smudged before it simply burns out. I've never had one fail catastrophically.
But ever since I saw the assembler's prints on the burned out one, I always give them a wipedown with ethyl alcohol before installing them. And they seem to last a lot longer. I do the same with qtz halogen auto lamps also.
Jim
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I've had ordinary quartz bulbs fail explosively. These were in 500 to 2000 watt studio luminaries. They sound like a 12 gauge shotgun when they fail. Same reason, fingerprints. The 300 watt quartz work lights from the usual sources fail the same way, though not quite as loudly.
Gary
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I have a 50w 12 V dichroic lamp in my workshop, powered by a PC power supply. put the lamp on the 12Volt lines (black-yellow), and put a taillight bulb (maybe 2) on the black-red lines (5 volts, will glow dimly). the PSU needs load on the 5 volt lines to regulate itself by.
a PC psu will supply about 8 amps at 12 volts, soft start, overvoltage protected etc. very nice to lamps in other words
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On Fri, 10 Oct 2003 14:40:44 +0000 (UTC), DejaVU

I have an Acra-View Optical Comparator, and the bulb it came with was burned out. Checking around, the bulb was around $14 US. I checked the supply voltage, 9vts AC, so went down to the local auto parts store, and picked up a brake light bulb for a 6 volt system. Works fine, nice and bright and cost $1.89
Gunner
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