Article View: sci.electronics.components
Article #151Re: Best way to power array of LEDs?
From: Kevin McMurtrie
Date: Thu, 07 Nov 2002 09:59
Date: Thu, 07 Nov 2002 09:59
27 lines
2676 bytes
2676 bytes
In article <3DC9B37F.453F9C41@fanwap.com>, "Nucharin W. Jansen" <tong@fanwap.com> wrote: >http://www.ResurgentSoftware.com/Perfect_LED_Light.html > >He parallels all LEDs together without any resistor to >constant voltage regulator. > > >At last week, I thought the same as him but I plan to do with >MAX757 ( DIP300 ) stepup IC from batt only 1 or 2 cells. >But after read several articles here, I get confuse so much. > >^_^ Some LEDs have a high internal resistance (~100 Ohms) so they can be operated uniformly in parallel for high currents. It's not a good idea to do this unless the internal resistance is a specified feature of the LEDs. For white light, I've rigged up panels that were strings of: (-) ---- White --- White ---- Amber --- 47 Ohms --- (+12V) They were fairly uniform in brightness for high currents but the string was so picky about voltage that it was easier to put them all in series and hack together a step-up switching power supply.
Technical Details
Message-ID:
<mcmurtri-E9E6BB.01592107112002@typhoon.sonic.net>Path:
arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!logbridge.uoregon.edu!nntp-relay.ihug.net!ihug.co.nz!news.ticon.net!feed.news.sonic.net!typhoon.sonic.net!not-for-mailReferences:
<0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <Rsan9.14070$qh1.1622310@news.ca.inter.net> <2Qan9.3129$cS4.107732@news2.tin.it> <3DC843FE.4A25FFF3@fanwap.com> <aqblsd$10119$1@hades.csu.net> <3DC99AD4.2AB0FE52@fanwap.com> <3DC9A173.812F4764@fanwap.com> <3DC9B37F.453F9C41@fanwap.com>Show Full Headers
Complete Article Headers
X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 112d1e,4ef4c9d4aea85e1f X-Google-Attributes: gid112d1e,public X-Google-Thread: 10d137,4ef4c9d4aea85e1f X-Google-Attributes: gid10d137,public X-Google-Thread: 103407,4ef4c9d4aea85e1f X-Google-Attributes: gid103407,public X-Google-Thread: 1131b0,4ef4c9d4aea85e1f X-Google-Attributes: gid1131b0,public X-Google-Thread: 1118be,4ef4c9d4aea85e1f X-Google-Attributes: gid1118be,public X-Google-ArrivalTime: 2002-11-07 02:00:08 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!canoe.uoregon.edu!logbridge.uoregon.edu!nntp-relay.ihug.net!ihug.co.nz!news.ticon.net!feed.news.sonic.net!typhoon.sonic.net!not-for-mail From: Kevin McMurtrie <mcmurtri@sonic.net> Newsgroups: sci.electronics.components,sci.electronics.design,alt.engineering.electrical,aus.electronics,sci.electronics.repair Subject: Re: Best way to power array of LEDs? References: <0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <Rsan9.14070$qh1.1622310@news.ca.inter.net> <2Qan9.3129$cS4.107732@news2.tin.it> <3DC843FE.4A25FFF3@fanwap.com> <aqblsd$10119$1@hades.csu.net> <3DC99AD4.2AB0FE52@fanwap.com> <3DC9A173.812F4764@fanwap.com> <3DC9B37F.453F9C41@fanwap.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit User-Agent: MT-NewsWatcher/3.2 (PPC Mac OS X) Message-ID: <mcmurtri-E9E6BB.01592107112002@typhoon.sonic.net> Lines: 27 Date: Thu, 07 Nov 2002 09:59:21 GMT NNTP-Posting-Host: 208.201.231.97 X-Complaints-To: abuse@sonic.net X-Trace: typhoon.sonic.net 1036663161 208.201.231.97 (Thu, 07 Nov 2002 01:59:21 PST) NNTP-Posting-Date: Thu, 07 Nov 2002 01:59:21 PST