While I understand the Persistance comment, I don't think this is it. A
couple of things. The eye has to convert the light energy to chemical
reaction/change and this takes energy. The perception, therefore, would
also be a factor of energy and a short pulse has less energy than a long
pulse, so this would bring you back into the average vs, RMS discussion and
favor the RMS idea. In other words, One would think power is what is being
received, just like our ears, so the RMS idea seems to have merrit.
However, I recall reading that the eye is a "somewhat" peak detecting device
(my paraphrasing of part peak / part RMS) and that was the reason (or part
of the reason) that the pulsed LEDs looked brighter.

BTW, shining the LED onto a surface would have the same argument, so
"_staring_ at a bank of leds" isn't a factor.

73, Steve, K,9.D;C'I

"Allodoxaphobia" wrote in message
...
On Fri, 14 Oct 2005 16:11:05 GMT, Asimov wrote:
"Roger Conroy" bravely wrote to "All" (14 Oct 05 09:06:17)
--- on the heady topic of " Pulsing LEDs for higher efficiency"

RC From: "Roger Conroy"
RC Xref: core-easynews rec.radio.amateur.homebrew:88243

RC If the brightness of an LED is a 1:1 linear relationship with the
RC power supplied, that suggests that perceived brightness of a
pulsed
RC LED would be neither at the arithmetic mean (average) nor at the
peak
RC but rather at rms (root mean square). Comments?

I'm pretty certain it is not a simple rms function because the
duration of the visual persistance effect must be taken into account.
If the peak brightness duration is long enough it will be perceived as
brighter than the average.

Perhaps. But, will it _illuminate_ any better?
The OP wasn't interested in _staring_ at a bank of leds. :-)

Maybe better discussed in rec.bio-tronics HI!HI!

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
Pueblo, Colorado | @ | Jonesy | OS/2 __
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