Article View: sci.electronics.components
Article #255Re: Best way to power array of LEDs?
From: budgie
Date: Sat, 05 Oct 2002 15:02
Date: Sat, 05 Oct 2002 15:02
42 lines
2962 bytes
2962 bytes
On Fri, 4 Oct 2002 12:43:55 -0700, DaveC <anon@example.net> wrote: >On Fri, 4 Oct 2002 1:40:30 -0700, budgie wrote >(in message <3d9d5392.5143261@news.cantech.net.au>): > >> In the auto situation, the simplest mitigation is to feed the >> resistor/LED chain thru an LM317 configured as a constant current >> source. Just the IC and one resistor added, and no voltage variation >> issue. > >The resistor you speak of is the voltage-drop resistor calculated for the >entire LED array? Or is this a biasing resistor for the LM 317? It "programs" the current you wish the device to pass. 1.25V across it at the load current you want. >Will this technique with an intermittent supply (press the brake pedal >and...)? Yup, fine for source voltage on/off. > A propigation delay? Current spike? propagation delay is probably nanosecs - hardly an issue. current spike? Not that I can envisage. >Sounds like an elegant solution, if it works well with the on again-off again >supply. >-- >Note that my return address is corrupted in an attempt to reduce spam. If you >choose to e-mail me, please correct my address as described below. > >Thanks, >Dave >--- >Dave Carpenter >Sound Logic >voicebox@d8n8a8i.com > >Remove the numbers to reply via e-mail >
Technical Details
Message-ID:
<3d9efe6a.1612340@news.cantech.net.au>Path:
arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!news1.optus.net.au!optus!news.uwa.edu.au!nntp.waia.asn.au!nnrp.waia.asn.au!not-for-mailReferences:
<0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <3d9d452f.4128065@news.xs4all.nl> <P0HAA5Jd3Un9EwWS@ntlworld.com> <3d9d5392.5143261@news.cantech.net.au> <0001HW.B9C33D8B00C077D3165FEAC0@news.covad.net>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: 1131b0,4ef4c9d4aea85e1f X-Google-Attributes: gid1131b0,public X-Google-Thread: 103407,4ef4c9d4aea85e1f X-Google-Attributes: gid103407,public X-Google-Thread: 10d137,4ef4c9d4aea85e1f X-Google-Attributes: gid10d137,public X-Google-Thread: 1118be,4ef4c9d4aea85e1f X-Google-Attributes: gid1118be,public X-Google-ArrivalTime: 2002-10-05 08:06:07 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!news1.optus.net.au!optus!news.uwa.edu.au!nntp.waia.asn.au!nnrp.waia.asn.au!not-for-mail From: budgie@nowhere.cantech.net.au (budgie) Newsgroups: sci.electronics.components,sci.electronics.design,alt.engineering.electrical,aus.electronics,sci.electronics.repair Subject: Re: Best way to power array of LEDs? Date: Sat, 05 Oct 2002 15:02:30 GMT Organization: CanTech Online Lines: 43 Message-ID: <3d9efe6a.1612340@news.cantech.net.au> References: <0001HW.B9C26E7400A7161B165FEAC0@news.covad.net> <3d9d452f.4128065@news.xs4all.nl> <P0HAA5Jd3Un9EwWS@ntlworld.com> <3d9d5392.5143261@news.cantech.net.au> <0001HW.B9C33D8B00C077D3165FEAC0@news.covad.net> NNTP-Posting-Host: proteus.cantech.net.au X-Trace: nnrp.waia.asn.au 1033830057 14694 203.26.6.6 (5 Oct 2002 15:00:57 GMT) X-Complaints-To: usenet@nnrp.waia.asn.au NNTP-Posting-Date: Sat, 5 Oct 2002 15:00:57 +0000 (UTC) X-Newsreader: Forte Free Agent 1.21/32.243 Cache-Post-Path: proteus.cantech.net.au!unknown@ra172.cantech.net.au X-Cache: nntpcache 2.3.3 (see http://www.nntpcache.org/)