I expose pcbs with a cheapo 500W halogen work lamp.Exposure time ~30 minutes..Could I reduce the exp time with an auto HID projector lamp? (Scrapyard. BMWs I think. Who hasn't been blinded by those suckers.)I see blue light from those HID lamps.If there's more blue end, than perhaps there's more UV too?It's probably not a big spectral span from blue to the UV band.A point light source is supposed to be best for exposing circuitboards..A projector makes a nice spot. UV tubes radiate radially.I have no idea how this difference in directionally has on theexposure quality.Anybody seen a spectral graph for those automotive HID lamps?I tried to Google up a spectrum.. Nothing yet.Note: UV tubes are not easily found around here but I'm surrounded byscrap yards.. :)D from BC

As far as I know, the HID stands for High Intensity Discharge - inother words they are compact arc lamps.The envelope is probably doped to block the hard ultra-violetcomponent.Note that arc lamps are something of swine to drive - the sloperesistance tends to be slightly negative, so you need a releativelyhigh impedance source. On eof my old colleagues developed the drivecircuit that BMW used when they first introduced the lamps - if youget the lamp from a junked top-end BMW, don't forget to get the drivecircuit at the same time.--Bill Sloman, Nijmegen

Automotive HID Projector Lamp Exposing a PCB?

Dec 19, 2007 24 Replies

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D from BC 18 years ago

But I'm thinking about using a collimated UV light source. I don't know if I'll get the best results with a UV tube that radiates radially.

\\|/ tube --O-- /|\\

-- --- --- transparency / \\\\

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a7yvm109gf5d1 18 years ago

Or maybe they like how women react to that kind of alpha-geek power.

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HapticZ 18 years ago

arc box at my old employer was a mechanical drive that kept the carbon rods spaced.

current sensors adjusted the movement to retain a suitable arc during pc board exposure.

much like a stepper solenoid and ratchet

old school stuff, but very reliable.

it made every radio in the neighbor hood a useless noisebox during operation too. :-))

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HapticZ 18 years ago

hobby guys love gettin down and dirty!

gloves are cheap, unprotected chemicals are a childs nightmare.

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HapticZ 18 years ago

yes, put the wife to work making them !!! ;-))

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