Newsgroups: sci.electronics
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From: willisw@willisw.ENG.CLEMSON.edu (Bill Willis)
Subject: Re: help me, i'm not clever! (how to make power supply?)
Message-ID: <willisw.16@willisw.ENG.CLEMSON.edu>
Keywords: power supply
Sender: news@hubcap.clemson.edu (news)
Organization: Engineering Services, Clemson University
References: <94318@hydra.gatech.EDU>
Date: Fri, 23 Apr 1993 13:10:47 GMT
Lines: 37

In article <94318@hydra.gatech.EDU> gt4417a@prism.gatech.EDU (SKELTON,JOEL PHILLIP) writes:

>I need to make a power supply that can take input from a 
>cigarette lighter in a car (12v dc) and drive 7.5 volts
>at up to 3.0 amps. I know enough to know that a simple
>voltage divider with two resistors won't do it right. Can
>such a thing be made from Radio-Shack-able parts without
>too much difficulty?

>jps
>bf

>p.s. I've looked for premade things like this at radio shack but
>none of it seems to go any higher than about 800mA.


>-- 
>Joel Skelton   --    North Avenue Trade School, Dept. of Round Things
>gt4417a@prism.gatech.edu   (ask for Scooter Technologies, and receive)

See if Radio Shack has a National Semiconductor Adjustable Voltage 
Regulator, (National) part number: LM350T or LM350K.  These devices are 
rated for an input to output differential of up to 35 Volts @ 3 Amps.

Digi-Key Corp. has these parts, as well as several other useful regulators.
If you don't have their catalog, their phone number is: 1-800-344-4539.

I can only guess that you may intend to recharge a 7.5 VDC nicad battery 
with this device, and if I'm right, you may want to look through some of the 
hobbiest books to get various ideas for battery charging circuits, first.

If you get stuck, e-mail me your FAX number, if you have one, and I'll send 
you some suggestions or schematics.

e-mail: willisw@coe-nw.clemson.edu


