> Here am I, trying to figure out what the deal is with DC 
> power jacks. What do PICListers use most commonly?

2.5 mm inner pin. slightly more robuust than the 2.1 inner pin.

I prefer center pin = positive because that reminds me of coax cable
(ground is outer).

> However, when I actually go to buy some, there seem to  be 30 
> or 40 different types and sizes. Even Radio Shack seems to 
> have come up with 21 different types.

Check what is supplied when you buy a universal wall-wart, here I get
some 10 plugs with it.

> Incidentally, the reason 
> why I'm asking about this is because I'm about to build a 
> clone of a certain device that was just fried by an adapter 
> that claimed to output 12V but instead put out 18V.

For an unregulated adapter that is quite normal. When I put a power
connector on anything I make sure that is accepts a wide range of
voltage, and survives inverse polarity. Most gadgets I see seem to be
designed likewise, but I recently got a USB hub that uses a stabilised
5V DC wall-wart. That gives me the creeps.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 
 

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