Date:         Sat, 7 Aug 2004 17:01:17 -0700
Reply-To:     laurasdog@WEIRDSTUFFWEMAKE.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Steve Delanty <laurasdog@WEIRDSTUFFWEMAKE.COM>
Subject:      Re: voltage converter needed.  12vt to 3vt
Comments: To: Doug in Calif <vanagon@ASTOUND.NET>
In-Reply-To:  <001401c47cb2$28b2dcd0$49d2ea42@ttower17def>
Content-Type: multipart/mixed; x-avg-checked=avg-ok-619075CF;

Doug,
I'd use a LM350.
It's a 3 amp adjustable regulator. It needs a couple external
resistors to set the output voltage. I would also use a small
ceramic capacitor from the input to ground, and the output to
ground for stability. 0.1uF @ 100volts would be a good cap
choice.

It will NEED to be on a heatsink. If you want 3 volts at 2 amps,
it means the regulator will dissipate 12.6V - 3V= 9.6V X 2A = 19.2 watts.

Here's a data sheet for the LM350....
http://www.national.com/ds/LM/LM150.pdf

Steve


---------------------

At 12:10 PM 8/7/2004, Doug in Calif wrote:

>Hi all,
>I am looking for a good simple reliable way to run a 2.4 volt cordless
>screwdriver motor hard wired to the vanagon 12 vt system.
>
>The only thing I have found is a converter at radio shack that costs 20
>bucks that will convert 12 vt to 3 volt at 1.2 amps.
>
>I want to run a cordeless screwdriver motor hardwired to 12 vts.  I need a
>couple amps. at 2.4 or 3 vt would be okay.
>
>Any simple suggestions like using a heater blower resistor?
>
>Doug