Why are mains transformers so big

hi,

why are mains xfmrs so big compared to the xfmrs in switch mode power supplys?

thx. Alf.

Transformers working at higher frequencies can be smaller with ferrite cores, instead of laminated steel. I can't remember exactly why - something to do with the ease of magnetic coupling.
So switch mode power supplies run at a high frequency.

You want them smaller...study electromagnetic theory and become an electrical engineer.

They would gladly accept help optimizing the design.