pls tell where to buy core of transformer
 

I want to make an output tranformer but don't know where to get the core

The easiest place to get the core.... is from another transformer.

Order some standard xfmers from Hammond or another supplier and have them delivered by UPS. You will likely receive loose, separate cores after they sort out that they shipped them to the wrong address first.

Actually, Hammond (because the Guelph plant is not far from me) is where I would go if I needed a xfmer core to wind something on that needed special thin steel stampings and not the usual power xfmer iron.

http://www.tempel.com/products/products.html

http://www.thomas-skinner.com/transf...aminations.htm