Re: DIY light source for 10X10" enlarger.

In article <Y5GdnZEVdsyC42PanZ2dnUVZ_tyknZ2d@[EMAIL PROTECTED]
>,
 "Nicholas O. Lindan" <see@[EMAIL PROTECTED]
> wrote:

> "Richard Knoppow" <dickburk@[EMAIL PROTECTED]
> wrote.
> 
> > I have no idea of what differences there are in the balasts [for cold 
> > light enlarger heads] other than to withstand intermittent operation.
> 
> Fluorescent lamps are one variety of gas-discharge lamp.
> They share their major electrical characteristic - negative
> resistance - with HID/Mercury/Sodium lamps.  Negative
> resistance means that as the lamp current increases the
> lamp voltage decreases and thus the current, unless
> limited, quickly rises to near infinity (i.e., a lightning
> bolt discharge).  The ballast's purpose is to limit the
> lamp current.

Does that mean if the ballast is fried and current is still some how 
going to a tube and one is standing on a aluminum ladder ones kiester is 
in serious jeopardy :)

-- 
Reality is a picture perfected and never looking back.