Wednesday, January 27, 2010

Transformerless Power Supply

This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance; and it doesn't generate very much heat.The circuit draws about 30ma AC.If you need more current, use a larger value capacitor; or put two in parallel; but be careful of what you are doing to the Watts. 

The low voltage 'AC' is supplied by D1 and D8.Also you can replace R3 and D3 with a 78 Series regulator.


  u1,   100ma fuse
   R1,   100 ohm ,  0.25watt
   R2,   1K ohm,   2 watt
   R3,   1k ohm ,  0.25watt
   C1,   470nF,  400v, polyseter
   D4-D7,   1N4001 or 1N4007
   D1, D8,   16v Zener Diode
   C2,   1uF  electrolyte
   D2,   12v Zener Diode 

1 comment:

  1. A power supply unit also known as PSU is the components which supplies power to the computer, more specifically a power supply is typically designed to convert 220-240V. mil-spec power supply