12V @ 80mA Transformerless Power Supply

        
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In electronics field, generating low voltage DC from AC mains (220V/110) is often necessary. Many electronic circuits work at an input voltage levels of 5V or 12V etc. For such circuits a transformer has to be used to step down the AC mains voltage to the required DC voltage level. Though using a transformer is the most familiar method, it has some dis-advantages, its expensive, it’s heavy and it has big size. The circuit presented here can supply an – non isolated from mains – output voltage of 12VDC for an input of 85-265 VAC without using a transformer.

Features:

  • Input (V): 85V AC to 265V AC
  • Output (V): 12V DC
  • Max Current: 80mA
  • PCB:70mm X 38mm

Notes:

  1. The above circuit deals with lethal AC voltage levels. Its very dangerous to work with it, without proper experience and precautions!
  2. Extreme caution is advised while experimenting/building this circuit as the output isn’t isolated from mains.
  3. The components are close to what shown in the 3D preview
  4. Use heat sink for components wherever applicable

Schematic

Parts list

PCB

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