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PCB light box - hf ballast / tube wattage

When buying an HF ballast and fluorescent tube does the ballast wattage have to match the tube wattage?

Is it allowable to use an hf ballast of higher wattage that that of the tube e.g. hf ballast 40W tube 12W ?

Can you parallel tubes to an hf ballast intended for a single tube so long as ballast wattage is sufficient ?

I am building a uv-a light box for sensitised PCB exposure and am not sure how many tubes to use. I am thinking get a higher wattage than needed hf ballast and say two 8 or 12W tubes so if there is insufficient light I could get one or two more tubes and parallel them.

Thanks

Reply to
Alt Beer
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The material you are using on the board should specify the light intensity, spectrum, and exposure time needed.

Tom

Reply to
Tom Biasi

match the tube wattage?

e.g. hf ballast 40W tube 12W ?

ballast wattage is sufficient ?

many tubes to use.

tubes so if there is insufficient light I could get

Light boxes with fluorescent tubes cast fuzzy and non-uniform shadows. It's better to approximate a point source some distance away. The sun does that. I've used a warehouse-type mercury vapor lamp, like a street light, 250 watts I recall, overhead about 4 feet away. Great resolution. Sun lamps work well, too.

--

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
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Reply to
John Larkin

to match the tube wattage?

e.g. hf ballast 40W tube 12W ?

ballast wattage is sufficient ?

how many tubes to use.

tubes so if there is insufficient light I could get

I have a hard rubber block with clamps and glass plate... put board in there and take it outside :-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

Lithographic "plate makers" do that. A vacuum frame atop a 4 foot high box, with an ordinary mercury vapor lamp at the bottom.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)
Reply to
Fred Abse

Back when I worked for a company that made microwave oscillators on contract for the military (circa 1970) the shop had a large vacuum plate and an actual carbon arc for exposure.

Reply to
Tom Biasi

What do you do when it's cloudy?

Reply to
fungus

Where Jim lives the skys are not cloudy all day.

Reply to
Tom Biasi

And the Buffalo fear to roam...lest they end up on his grill...

Reply to
Michael A. Terrell

I had buffalo at the Pilot's Club in Denver some years back... it's too-oo-oo lean, and sort of bland. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

My wife gets bison burgers once in a while. They are lean but I wouldn't call them exactly bland. Ted's (Ted Turner's restaurant) down the street from work has them, too. A lot of vendors want to take us there but I always have the beef burgers. Buffalo is over-hyped.

Reply to
krw

You could feed it a couple liberals to fatten it up, and add all the spices you want. ;-)

Reply to
Michael A. Terrell

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