I just took apart a flyback transformer for a 40W flyback for which the core was said to have a 2mm gap.
However, the core pieces are ETD24 and have no visible gap.
also there was no spacers used.
....so, do you know what going on.
The transformer did nt saturate so must have had a gap.......could it be that it is ferrite core pieces made with special ferrite that have the gap "integrated"?
It "surely" can, review e.g. Magnetics data sheets. If you're not colour-blind, you should recognize the difference. Powder cores have a slightly brownish or "warm" grey shade, opposite to black til neutral grey ferrite. It should be noticed that an E-core isn't magnetically optimal for a "distributed" air gap design, but it's used though for ease of winding.