Electrical schoolwork...

[Ameer Antar]

1/2W should be plenty in almost any case. It's interesting to note that Audi designed their own red window switch LED circuits w/ 1/4W resistors which are probably very close to the actual power dissipated through the resistor. You'll be OK if the power calculated is .2W and you use a .25W res., but make sure you use a little extra resistance (you'll never find a resistor w/ the exact value you want). Although margin of safety is important when your talking 30W+, at a 1/4W, this is not a lot of heat, so close enough is close enough. If you have an old window switch, you might want to just use the same value as they did. good luck.

-Ameer

---Original Message---
>
>To: Louis-Alain RICHARD <laraa at sympatico.ca>
>From: Bernard Littau <bernardl at acumenassociates.com>
>Date: 2/10/2004 3:49:31 AM
>Subject: Re: RE : Electrical schoolwork...
>
>Just go to Radio Shack and purchase some of their 12V DC red LEDs.  They 
>have the resistor built in, so no messing with calculations of ohms and 
>WAGs of resistor current capacity (sheesh, 1W resistors).  Should be 
>close to a drop in replacement.
>
>See:
>http://www.audifans.com/pipermail/200q20v/2003-August/015644.html
>
>I assume that is a current part no. for the RS LEDs.
>
>Best,
>
>Bernard
>
>Ti Kan wrote:
>
>>Louis-Alain RICHARD writes:
>>  
>>
>>>if it was feasible to replace only the bulbs: negative...). But now if I
>>>have to package a big 1W resistor IN the switch, it might me very
>>>challenging.=20
>>>    
>>>
>>
>>You're probably ok to raise the resistor value to limit the current a
>>bit further and just use 1/2W resistors.  Usually a factor of two
>>change in resistance only yields a marginal difference in perceived
>>brightness, assuming that both are within the LED's nominal operating
>>current range.
>>
>>-Ti
>>2003 A4 1.8T multitronic
>>2001 S4 biturbo 6-sp
>>1984 5000S turbo
>>1980 4000 2.0 5-sp
>>  
>>