In a message dated 10/6/2005 8:39:06 PM Central Standard Time,
tr3driver@comcast.net writes:
> >A sizeable capacitor on the switched lead may help too.
>
> 1000 microfarads (abbreviated mfd or sometimes uF) should make a difference,
> if
> that is the problem. More won't hurt anything, but the 0.5 farad or 1.0
> farad
> "monster" caps are certainly overkill. Used to be you could buy used
> 100,000
> mfd caps at any hamfest for a couple of bucks, but I have no idea if that's
> still true (or even if they still have hamfests).
>
>
The larger the capacitor the greater the inrush current issue will be.
Slamming a 1 farad monster cap across a 12 volt battery through the key switch
contacts will likely shorten the life of the switch significanly. It will also
take a significant amount of time for the small amount of current that input
uses to discharge the cap so the radio will continue to play after the key is
switched off (although GM has made this a feature).
Check the radio specs but usually this input is only a control signal and the
main power comes through the constant feed. If the current is low enough a
small resistor, say 22 ohms or so may be a good idea.
On the other hand, if htis is only a control signal input it may be
impervious to noise anyway.
Dave
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