Amazon.com: AC-DC 5V 800mA Buck Converter Step Down Board 110V 220V to DC 5V Transformer Power Supply Module for Arduino Voltage Isolation : Electronics
Mains AC / DC Converter with SR03x - Power Supply Circuits
How to make Regulated Transformerless Power Supply At DIY 220v AC o DC 5v,6v,12v - YouTube | Power supply design, Power supply circuit, Basic electronic circuits