The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Spehro Pefhany"
Subject: Re: What is maximum current for LED?
User-Agent: tin/pre-1.4-19990216 ("Styrofoam") (UNIX) (Linux/2.2.14 (i586))
Date: Thu, 03 Oct 2002 17:06:21 GMT
NNTP-Posting-Date: Thu, 03 Oct 2002 13:06:21 EDT
The renowned Malcolm Reeves wrote:
> Surely since diode voltage is constant-ish then the loss is
> proportional to I (ish). Power to light conversion is so low you
> could ignore it for heat purposes.
Okay, looking at the first LED manual on my shelf and the graph that's
easiest to read (GaP green), consider a 4:1 current range.
Vf = 2.08V at 10mA
Vf = 2.50V at 40mA
Power dissipation in LED at 10mA is 20.8mW
Power dissipation in LED at 40mA/25% duty cycle is 100mW peak/25mW average
About a 20% increase.
(I suspect newer low end commodity LEDs may be even worse in this regard
as the trend is to use smaller dice to reduce cost).
"it's the network..." "The Journey is the reward"
firstname.lastname@example.org Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup