[ale] OT: Office lighting

Tue Apr 30 12:42:01 EDT 2002

"Michael H. Warfield" wrote:
>         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).

One problem is with monitors refresh rate having a beat frequency with the
fluorescents.

-- 
Pete Hardie                   |   Goalie, DVSG Dart Team
    posting from, but not     |
	speaking for:             |
Scientific Atlanta, Digital Video Services Group

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