John Woodgate wrote:
In message , dated Tue, 8 Aug
2006, Mark Fortune writes


You need more than 5 A AC to get 5 A DC. The rough rule is that a bridge
rectifier needs a factor of 1.6 times, but with modern huge filter caps,
think of at least 1.8 times. That's a BIG transformer, with THICK
secondary wire. Not a project to learn on, I would say.

I think what you're saying is "try learning on some smaller transformers
first" I might just do that, cos it'd be a PITA if I screw up on a big
one and have to unwind it all again :]


It's not even easy to buy parts for transformers now. Maplin used to do
kits - bobbins, laminations etc. , but not now.

To learn about transformer design, you need a textbook and one of the
best is a classic - Radio Designer's Handbook, by F Langford Smith,
which was reprinted by Newnes (Butterworth-Heinemann/Reed) a few years
ago. ISBN0 7506 3635 1.

Thanks for the info, i'll try and get my library to order a copy.


Modern core material (silicon-iron) is better than the materials
mentioned in the book. You may be able to get the information on current
materials (maximum recommended induction, core loss power/kg,
magnetizing VA/kg) from the web.

I'll have a look, thanks