Semi OT: [elec]LED gauge lighting

[juliemac57@hotmail.com (Julie Macfarlane)]

Better yet, contact either JDRmicrodevices.com or HP directly. They have 
white high intensity leds that would operate better. They also have other 
colors as well.
But... To protect the leds from  surges in current, place a diode (In4146 1 
amp diode. Radio shack again) in line between the supply and the resistors. 
reduce the drop voltage of the resistor by 0.7v.

This will stop the leds popping.



Julie Macfarlane
Menlo Park Research & Development
Internet Application Developer
Amsterdam NY





>From: "Allyn" <amalventano@sc.rr.com>
>To: <Cmr446@cs.com>, <scirocco-l@scirocco.org>
>Subject: Re: Semi OT: [elec]LED gauge lighting
>Date: Mon, 13 Jan 2003 18:49:15 -0500
>
>Carl,
>     You simply need the correct value resistor in series with the LED and 
>it
>will be safe.
>here is an example:
><http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=C
>TLG%5F010%5F012%5F002%5F009&product%5Fid=276%2D320>
>follow along with me:
>* this LED is rated at 20mA @ 3.6V. you intend to supply it with 13V
>(cluster light power).
>* 13V-3.6V=9.4V , meaning you need something else to drop 9.4V, in order to
>protect the LED.
>* therefore our resistor needs to carry 20mA at 9.4V.
>* 9.4V/20mA=470ohms
>     Place a resistor of that size (or slightly higher) in series with the
>LED and you can then wire it directly to your instrument cluster lighting
>supply. Furthermore, your dimmer will still work correctly as the resistor
>will help the LED respond linearly to changes in input voltage.
>hth
>Al (resident electronics geek)
>
>----- Original Message -----
>From: <Cmr446@cs.com>
>To: <scirocco-l@scirocco.org>
>Sent: Monday, January 13, 2003 6:00 PM
>Subject: Semi OT: [elec]LED gauge lighting
>
>
> >   I want to convert my gauge/instrument lighting over to white LED's, 
>but
>I'm
> > trying to figure out just how to do this. A quick trip to Radio Shack
> > provided a 1000mcd white LED at 3v, and the sales people had no idea 
>what
>I
> > was talking about when I asked if higher voltage and wide angle versions
>were
> > available. Other than that I did find out that I'll need to run a 470 
>Ohm
> > resistor on the LED, but would I need this with a higher voltage LED?
> >
> >   Any help before I turn my dash into a fireworks and smoke show would 
>be
> > appriciated! :)
> >
> > Carl
> > 77rocco
> > 89fox  - donor to be
> > 03saturn - 16v, 140hp, no soul...
> >
> > _______________________________________________
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> > Scirocco-l@scirocco.org
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> >
>
>
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