Transformer help

[Mike Nichting]

Hey all,
I have a 12.6 volt transformer that I want to use in a Tube Driver circuit instead of an adapter.
 Where is some good info that describes how to hook up a transformer??
I don't have any experience with these things.
It is a center tapped tranny so I know I don't want to use the middle wire but which one is negative and positive to hook up to the circuit board and which one is neg and pos to hook up to the plug??

Thanks all,
Mike N.

[brett]

Hi Mike.  This will be simple (I'm that kinda guy).

First, you're making a good move to get rid of batteries and use an adaptor.  In fact, you're an environmental champion!

Now, identify the primary side of the transformer.  It's NOT centre-tapped, and that'll be where you connect the wall plug.  It's not fussy about which way the power comes and goes (either wire can be the active or neutral).  Some folk like to put a small AC voltage rated cap across the inputs to cut out interference (but it's not essential).  An on-off switch should isolate both wires going to the transformer when it's "off".

You are already aware that you don't need to use the centre tap.  The secondary wires are connected to a rectifier.  You can use something like a W04 (400V 1.5A) or a 2W06 (600V2A), which is usually marked with a "+", a "-" and two "~" symbols.  The "~"s are the inputs (connect either way to the transformer) and the + and - are the outputs.  However, you'll need to send the + output thru a simple voltage regulator to get rid of the serious amount of "ripple" in the rectified signal.  A datasheet on most IC regulators, like the 7809 (7809 = 9V, 7812 =12V, etc) will explain what else is needed (usually a BIG cap to ground before the 7809 (e.g. 2200uF) and a couple of small caps (to ground) on either side.  Type "LM7809 datasheet" into a search engine and you'll get better info than I'm giving here.

I'm sure that I've forgotten some things (e.g. fuse/s).  Give us another post if you've got more questions.

cheers

[Mike Nichting]

Brett,
thank you very much. Well, it's obvious that I had no idea what I was getting into ;-)

 I will give it a go and post when I run into trouble. Which will be soon I'm sure. I'm not at all sure how to go about this but I will use your info here and try my best.
I am going to use a large toggle for the on/off switch since they stand up to abuse pretty well.

 I'll be back......;-)

 Thanks again,
Mike