Power supply

[Bill]

Where can I get a cheap power supply, about 120watts 12v output to sound a car horn? That is, something other than a car battery.

[scott21230]

How many Amps output do you need? Usually I can find what I want to use by looking through my box of leftowver plug in wall transformers for items that have broken and I've thrown out.

[Pete C.]

120W @ 12V = 10A

Pete C.

[digitalmaster]

buy a cheap car battery charger????

[Wayne]

You should be able to use a standard computer power supply I'd think. Just checked one here and it shows one of the outputs being 12v 10amp. Wayne

[higgledy]

allelectronics.com

Wayne wrote:

[Mark Lloyd]

I've seen some computer power supplies that will not work correctly unless the +5V output is loaded sufficiently.

[Jeff Wisnia]

If it's only going to be sounded once in a while, you might be better off buying a 12 volt sealed rechargeable "burglar alarm battery" and using an scrounged 12 volt DC wall wart to keeped that battery trickle charged.

That way you'd be able to have the horn sound even if the line power was out.

You might need to play around with a current meter and a handful of resistors to limit the battery charging current to an acceptable continuous level, but it isn't eggsackly something you'd need help from a Nobel laureat for.

Jeff

[Wayne]

Hi Mark Most PC power supplies have a legend on the casing which will tell you what colour has what specs. It shouldn't take much to work out which one will provide you enough load. We recently built a box to house a car stereo with amp and sub's for use on our back patio. Two PC power supplies makes the whole thing work nicely, can't see how it wouldn't provide enough for a car horn to work. Cheers Wayne