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In article ,
(listerofsmeg) writes:
Hi all,
I am setting up a CCTV system, which will have about 8 cameras.
Each of these cameras requires a 12V 200mA supply.
After a bit of research, it appears I can have one transformer (say
12V 2A), and take LV power lines off for the cameras in parrallel.
Does this seem right?
Yes, as long as the cable runs aren't too long with too
thin cable.
Ok, my problem appears to be finding a transformer!
Firstly, they seem to have different power ratings. Some are in amps,
some are in Watts, and some are in "VA"s whatever they are. Anyone
know how to work out one from the other.
You'll be wanting a DC supply, so ignore any with the
output rated in VA.
Secondly, everywhere I look seems to have these strange light, white
thin transformers that are primarily used to low voltage lighting. Can
I use one of these to power my cameras?
No, they output high frequency AC.
What I was really after was a good old "black lump" transformer that
plugs into a mains socket, but I can't find any of these online at
all! Are they called something different?
Try Maplin, CPC.
Cash Converters had a large bin of them in the shop for a
pound each, and I've often been able to find the rating I
want by rummaging through it.
--
Andrew Gabriel
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