Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!portal!cup.portal.com!John_A_Pham
From: John_A_Pham@cup.portal.com
Newsgroups: sci.electronics
Subject: Re: LED refresh rate
Message-ID: <30550@cup.portal.com>
Date: 5 Jun 90 20:15:48 GMT
References: <30513@cup.portal.com> <61580@sgi.sgi.com>
Distribution: usa
Organization: The Portal System (TM)
Lines: 18

In article <61580@sgi.sgi.com> rpw3@rigden.wpd.sgi.com (rob warnock) writes:
--In article <30513@cup.portal.com> John_A_Pham@cup.portal.com writes:
--+---------------
--| Can someone tell me what is the average time for a LED to fully lit
--| and vice-versa?  I remember it is around 3Khz or was it 300Khz?
--+---------------
--
--It depends on the LED, but more on the driving ciruits. I have driven
--the red LEDs in H-P low-cost plastic fiber-optic cables at 10 MHz and
--above. The 1300nm LEDs in FDDI controllers run at 125 megabaud (100 Mb/s
--of 4/5 coding). Even dirt cheap LEDs can be run at several megahertz.
--
--Of course, good luck trying to build a dirt cheap *detector*...  ;-}
 
     Ooops, I should make that clearer.  I want the refresh rate for LED
that a human eyes can tell between an OFF and ON cycle.  Heck, for 
1mhz or faster, LED will just fully lit to the human eyes
John