see this:
http://web2.murraystate.edu/andy.bat...OWERSUPPLY.HTM
http://www.wikihow.com/Convert-a-Com...b-Power-Supply
If you'r interested

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If is too complicated.....most of the times is the wrong way.

 

I've got literally half a dozen ways to get 12V power, including an AT power supply and a couple ATX supplies. I mentioned the wall wart because it happens to be what I've been doing most of my tinkering with (as it's cheap and expendable).

The real concern for me is getting from 12V to 8V cleanly, and now that's solved (I've got a handful of 7808s due to arrive Monday).

 

Wel..yes, but the entire discusion was revolving around fuses, 500mA rating etc. so I joined.
Btw....I'l rather use a LM317 for regulating the 8V. It's more reliable. But I gues it's to late for that.

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If is too complicated.....most of the times is the wrong way.

 

Oh? A 7808 lasts one million years. An LM317 lasts two million years. Does it matter?

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Uncle $crooge

 

lol: Good point lol: What could I say...I'm a 317 fan
All thought the 317 has several advantages like lower riple (not important for this app). Anyway, due to being a variable regulator the circuit can be easily modified for a diferent voltage, curent sources etc., whitch offers solutions for future projects. And I fried enought 78xx for not trusting them. lol:

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If is too complicated.....most of the times is the wrong way.

 

7808's aren't something you see very often?, but certainly 7805's, 7812's and 317's all die fairly regularly - they are pretty reliable, but poor enough for me to stock them for TV repairs!.

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PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

The LM317 does have better characteristics but it requires two external resistors while the LM78xx series don't. I don't know which is the most reliable though, my gut feeling would be the LM78xx series as there are less componants to fail.

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I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

I recommend that your first project is to build an LM317T based adjustable power supply. Use a wallwart for safety, but build everything past that yourself. There are plenty of schematics and plans available on the web.

A variable voltage supply will be very useful on down the road, and you will learn a lot by building one. It doesn't have to be fancy, just build it on perfboard and stick in in a cheap case of some kind. You will probably build a better one later on

"The Art of Electronics" is a great book, I have it, but a better book for beginners is "Getting Started in Electronics", by Forrest Mims

Good luck

- Rick

 

I've been pondering the need for a variable supply anyways for quite some time now, so I'll probably add that to my list of things-to-tinker-with.

Thanks for the book recommendation, I'll see if I can scrounge up a copy from the libraries around here.