Switch mode power supply design

[Enzy]

I build circuits as a hobby, I mostly build amplifiers and inverters. I normally build Linier power supplies if thats what its called with the regular iron core transformer but now I want to try using switch mode power supplies, right now I have a amplifier design I want to try and I would like to use a switch mode power supply but I can not find a schematic I would want because normally the power rating is too low, if its even correct I dont know how to build the transformer for it could I get some help.

 

[BradtheRad]

There are online calculators for smps.

It's a frequent topic here. See the list of related threads at the bottom of this column. Or do a forum search. Example, buck, boost, buck-boost, flyback.

I dont know how to build the transformer

Many find it is easier to start with a ferrite core, of a size rated to store the required energy. Then they wind it with a wire gauge which is rated to carry the desired Amperes.

As an experiment I built my own inductor, after looking at hobbyists' webpages. One describes mixing homemade ferrous slurry. Another site talked about cutting up steel wool into slivers. I tried that. I mixed slivers 50-50 with adhesive, and stuffed it into a soda straw 2 inches long. I wound magnet wire around it many times, and that gave me my homemade inductor. It has a small Henry value, and it is only suitable for low current levels.

To handle greater current levels, you can consider interleaving two or more converters. Or consider making a flyback, especially if you need to step up or down by a large ratio.

 

[schmitt trigger]

Another site talked about cutting up steel wool into slivers. I tried that. I mixed slivers 50-50 with adhesive, and stuffed it into a soda straw 2 inches long. I wound magnet wire around it many times, and that gave me my homemade inductor.

That is very clever, very clever indeed.
I would assume it has to be a non-viscous adhesive, like Elmer's glue. Correct?

 

[BradtheRad]

That is very clever, very clever indeed.
I would assume it has to be a non-viscous adhesive, like Elmer's glue. Correct?

Yes, the steel slivers make it difficult to push the mash into the straw. My attempts have used silicone sealer. It doesn't shrink much as it sets. I found I had to mix a lot with the steel slivers, just to have a mash that can be manipulated.

Certainly Elmer's is worth a try. It is runny, and shrinks as it dries, concentrating the steel slivers. That should increase the Henry value. I would like to be able to wind the wire inside the straw, then pour the mash. By bringing the wire into close contact with the iron particles, that should also increase Henry value.