31 May
2008
31 May
'08
8:30 a.m.
On Friday 30 May 2008, Tony Duell wrote:
Indeed...
I don't see what the problem is. There are much more efficient methods
of lighting, than the one that Edison worked a lot on over 100 years
ago.
In addition to compact fluorescent lamps, you can get LED-based bulbs,
halogen lamps (which still are effectively incandescent, but a bit
better), and various gas-discharge lamps.
After working on a SMPSU (or any power supply for that
matter,
but especially a switcher), I usually power it up to test
throught a light-bulb. [...] Has saved me from "secondary
catastrophic failures" on more than one occation.
And I've heard people talk about banning incandescent bulbs
entirely. Whele I use compact fluorescent bulbs a lot, there are
4 places where
I stick to the old filament lamps :
1) Over my lathe. There is significant 50Hz flicker from compact
fluorescents in my experience, I don't want the possible hazard of
thinking something is stopped when in fact it's rotating at a
multiple of the mains frequency
I don't think I've ever seen a CF that had a ballast that operated at
mains frequency. Usually, a switching supply that runs at many kHz.
Normal fluorescent bulbs, with a "magnetic" ballast instead of
an "electronic" ballast, though could produce your 50Hz flicker. CF
bulbs would need do be quite a bit bigger and heavier to have a 50/60Hz
ballast in them.
Between that, and the phosphor persistence of the bulb, I don't think
this could be a real problem. If it is, you could always just run a
fluorescent bulb off of a DC supply. :)
2) In my darkroom. CF's have a long afterglow when
you turn them off,
easily enough to fog film. I want a light source I can turn off
instantly
LED lights turn off much faster than Incandescent bulbs do. Plus, it's
easy to get/make one that produces red light. :)
3) In my copying stand, where I need a contimuous
spectrum of light
Halogen? There are fairly good spectrum flourescent bulbs available
these days, but I've not tried to look at them through a prism.
4) In my SMPUS current limiter, for obvious electrical
reasons.
Halogen? Maybe a properly engineered RL circuit instead of some
cobbled-together light-bulb current limiter. :)
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org