How to get 12V/5V from a 25V AC toroidal transformer.

I'm in the process of building a small stepper controller box to house three PICSteps to control my little Widgitmaster machine. I've mounted a 25VAC toroidal transformer inside the very small case and it outputs around 36VDC once rectified which is perfect for PICStep. But I also needed 12V to supply a small fan to keep the drivers cool and I also needed 5V to supply the logic side of PICStep.

I originally thought about using a DC-DC converter to drop the 36VDC down to 12V and then use a 7805 to bring the 12V down to 5V but it seemed overly complex and time consuming to do. Then I thought I'd add an additional small transformer for the 12V and that didn't work out purely because the internals of the case are such that it would be really hard to work on.

Then I thought about it some more, and as I was sorting through my spools of enamelled wire looking for something unrelated I thought, "hmm I've got this bunch of magnet enamelled wire, plus I'm using a toroidal transformer.", "why don't I just wind another secondary winding onto the existing toroidal to supply this 12V"?

So anyway after a little experimentation and about 25 minutes of winding 30 odd winds of enamelled wire around the toroidal I have a very good 12V DC supply! I now have a simple small bridge rectifier with a capacitor to supply unregulated 12VDC to the fan, and the same 12VDC is fed to my break-out board that has a 7805 for the regulated 5V. Works like a charm!

The only thing I wish I did a little differently was only put enough turns to make it output about 9VDC instead, as the 12V fan running at full speed is quite loud and the 7805 probably wouldn't mind having to deal with a few less volts. Oh well it works. :)