Re: confused about transformers

[Scott M]

In simple terms VA is used to refer to power (Watts) but is used to refer to the AC side of things. A Watt is simple Volts x Amps (and hence VA.)

So you want a PSU that'll give you 12v and at least either 20Watts or

20VA or 1.6amps. And a DC output!

[Paul]

Lister,

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?

Yep, no problem.

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? After googling a bit there are > reports that these throw off a lot of RF interference which is no good > to me. Also I will have some pretty long cable runs (20 meters), and I > have read that some have restrictions on cable length.

The cable length restriction is probably when using them in conjunction with LV lighting, as the current draw of the bulbs is high, the volts drop down the cable is significant and can shorten the life of the bulbs. Personally I wouldn't use one of these for what you are doing.

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 looking here

of what your looking for !

You could also use a CB Radio power supply, these are generally 13.8 volts, but there is plenty of power (normally 4 amps or so) and have a nice smooth regulated output.

Good luck,

Paul.