[TenTec] dial lights for OMNI D and Model 544 Triton

[Douglas]

> Date: Fri, 7 Jun 2013 16:24:26 +0000 (UTC)
> From: davkozy at comcast.net
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Subject: Re: [TenTec] dial lights for OMNI D and Model 544
> Triton
> Message-ID:
> 
> How do you determine the proper resistance? 
> 
> Is it try different values until you find the intensity you
> desire? 
> 
> 
> 
> Does anyone have suggestions for combinations that match the
> exixiting lamps? 
> 
> 
> Dave K. 



Just use basic Ohm's law with the following assumptions:

The average LED will have a current draw at full brightness of about 20 MA (.020 amps). 
If in doubt, try to look up the specs via the LED's type number but 20 MA for smaller LED's has worked fine for me.

Assuming a voltage drop across the LED of .7 volts, subtract .7 volts from your supply voltage.

If 12 volts you need to drop 11.3 volts at .020 amps, R= E/I or
R= 11.3/.020 = 565 ohm.

73,

Doug/WA1TUT