DIY AC-to-DC 12V Flyback SMPS For Beginners

[hesam.moshiri]

The isolated AC-to-DC flyback converter is the most commonly used power supply type for home and industrial devices. Fear of the main voltage and complexity of calculations cause electronic beginners and enthusiasts to procrastinate DIY such circuits. This project introduces an AC-to-DC flyback switching power supply that converts universal 50Hz AC input (85V-260VAC) to 12VDC-0.5A (6W) using the minimum components in the BOM, both price and quantity.

CAD: Altium Designer, Altium-365
Tools: Siglent SDL1020X DC Load, Siglent SDS2102X Plus Oscilloscope, Vevor SC240M thermal Imaging Camera

[floobydust]

What makes you think your power supply is safe? Any testing? Hi-pot?
I have an issue with you posting a design, empowering beginners to make a mains-powered SMPS- that is a theoretical, and possibly unsafe design.
Your spacings - creepage and clearance have problems. What was your goal?
Your trace spacings under the bridge rectifier are inadequate and too thin in general. Did you set a rule in Altium?
You never put a ground-pour under an opto-coupler/Y-cap. The transformer mounting pin G2 is also close to the secondary-side ground pour, and cores are not treated as insulated.
You have no safety discharge resistor for the filter capacitor C1.

Where are the transformer winding details? Any insulating tape in there? How much?