In article ,
"Pedro Popadopolous" writes:
Any help greatly appreciated. 500mA needed

I want to run Camera's off these. Even better would be a single PSU that
could run upto 4 cameras @ 500mA each

I doubt a camera really needs 500mA unless it's got some extra
equipment such as lighting, screen wiper, etc. Might be worth
measuring what the actual demand really is.

Also, a regulated power supply won't be as well regulated at the
end of a long wire, which might be your situation if you have
one supply feeding several dispersed cameras. Are you sure it
needs a regulated supply? Cameras I've used all include the
regulation locally, specifically so they can run on long supply
wires. A single supply feeding over long wires to remote cameras
could create ground loops, degrading the video quality.

CPC were doing 9V 1A power supplies for 99p for many months, but
it looks like they have finally got rid of them all now as I can't
find them on their web pages. I have found small PSU's I've needed
for various things by rummaging in a bin full of them in
Cash Converters, for £1 each.

I would be slightly weary of a switched mode PSU for this application,
in case the switching frequency manages to break through into the
video output, where it could cause bad visual interference.

--
Andrew Gabriel