[ale] OT: Office lighting

[Michael H. Warfield]

On Tue, Apr 30, 2002 at 11:05:59AM -0400, Stuffed Crust wrote:
> On Tue, Apr 30, 2002 at 11:01:34AM -0400, Thompson Freeman wrote:
> > Flourescent is what I'm slowly putting throughout the house - makes it
> > easier to air condition. 8-) Putting the lighting & fan on a separate

> The problem I have with flourscent lighting is flicker.  They flicker at
> 60Hz, which is slow enough for me to be able to seee.. and gives me
> quite a headache if I'm around 'em for more than a couple of hours.

	Flourescent lights "flicker" at 120 Hz.  Think about it.  Current
flows alternating in two directions and one cycle takes place 60 times
per second.  That means that one current pulse flows one direction (one
flicker) then a second current pulse flickers the other direction (second
flicker) 60 times per second.  So you get two pulses of current resulting
in two pulses of light for each cycle of AC at 60 cycles per second.
2 * 60 = 120 Hz.

	If 120 Hz hurts (sorry, cheap pun) your eyes you've got bigger
problems.  Frame rate on a standard NTSC television is very slightly less
than 30 (29.97) Frames per second (Field rate, at 2 fields per frame, is
slightly less than 60 (59.97) FIELDS per second).  Movie house movies,
OTOH, would REALLY kill you at 24 frames per second (and no field / frame
interlacing - you get 24 pics per second period).

	So flourescent lights flicker 5 times FASTER than a convention
movie in a movie theater.  Somehow, I don't think it's the flicker rate.

	OTOH...  Flouresent tube are know to go unstable with plasma
streamers, pulses, and waves.  These can have interesting stroboscopic
effects, especially in the big commercial 8' bulbs.  That generally
indicates either a bulb that is about worn out or one that is not
properly matched to either it's ballast transformer or (in the case
of 4' or smaller bulbs) it's twin in a two-tube set.  All bets are off there.

	I agree with others.  Color temperature is a BIG factor with
background hum dragging in at a distant second.  Either of those are
much more likely to result in headaches than the base flicker of the tubes.

>  - Pizza
> -- 
> Solomon Peachy                                    pizzaATfucktheusers.org
> I ain't broke, but I'm badly bent.                           ICQ# 1318344
> Patience comes to those who wait.
>     ...It's not "Beanbag Love", it's a "Transanimate Relationship"...


	Mike
-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw at WittsEnd.com
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