Transformerless Power Supply

Description:

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.

Schematic:

Components:

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

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