Re: 18g wire good enough?

[sheridan@vanceandhines.com (Brad Sheridan)]

>At 18:31 3/19/97 -0600, you wrote:
>
>It probably is a potentiometer. A 'rheostat' would work if the extreme 'dim'
>end of travel was actually 'off'. This is how some older cars worked.
>

  I opened up the light switch after I had my dash fire, and there is a
rheostat(I believe) there. It appears to be  metal wire wound, which makes
it a rheostat, correct? I confess to not knowing , I usually deal only with
smaller stuff(pots and the like) and digital...

  BTW, that underdash short I mentioned was enough to blow the dimmer. From
what I remember, it somehow ruined the wiper arm of the dimmer. So I guess
there are limits to the current it can take, although I doubt anybody would
run that much current through it unless it was a short like my situation.

>The problem is not how much current the battery can supply (hundreds of amps!),
>but how much the dimmer can pass. I have not done any tests, but I would be
>suprised if it can handle more than an amp. For a pot to supply large
>amounts of
>current, it would need to be a low resistance, and this would get hot. Kinda
>like my buddy's Chevy Caprice, where the light switch gets uncomfortably warm

>A neat cure, for them who can figure the circuit, would be to use a fairly
>large transistor in a heatsink as the actual 'dimmer', while the potentiometer
>supplies base current, what is known as an 'emitter follower'. The pot can be
>a fairly high resistance in this case. If you send a FAX number, I will
>send the
>circuit.

 Scan it, and put it up on FTP space. If you don't have FTP space, let me
know. I have plenty of space available. I'm sure other people would be
interested in the design.

Brad


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