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: "Nucharin W. Jansen"
Subject: Re: Wanted circuits to power white LED from 1 nicad/nimh cell
Date: Thu, 07 Nov 2002 04:49:08 +0700
Organization: C.S. Communications Co. Ltd.
NNTP-Posting-Date: Wed, 6 Nov 2002 21:49:12 +0000 (UTC)
To: Bob Wilson
X-Mailer: Mozilla 4.8 [en] (Windows NT 5.0; U)
You mean I can't parallel LEDs without resistor, right ?
Can I use 10 ohm for each strings/branch ?
Bob Wilson wrote:
> In article <3DC839EE.4A3F0D24@fanwap.com>, firstname.lastname@example.org says...
> >I using MAX757 adjust voltage to 3.5V voltage regulator.
> >I can get 22uH inductor 1/4w ( look like resistor but green color )
> >The capacitor can use electrolye and don't worry about voltage ribble.
> >The problem is white LEDs itself!
> >Their are not the same voltage drop.
> >I parallel it up to 6 LEDs. These IC support 300mA output.
> >No reason the build smallest flashlight.
> >These IC can run down to 0.7v to 3.5v
> >Hope these help.
> Unless the LEDs are forward voltage matched, paralelling them will not work,
> because they will not share the current. The one with the lowest
> forward voltage will hog most of the current. There is nothing special about
> white LEDs. They are simply ordinary Blue LEDs, with a yellow phosphor
> added. The blue light pumps the phosphor to emit yellow (the compliment of
> blue), and there is enough blue leaking out that the mixture of blue and
> yellow combune and look white to the eye.
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup