Transformerless Power Supply

I have received a few emails asking for a transformerless power supply.
Here is such a supply. This supply uses no heavy step down transformer
and has an extremely low parts count. The circuit can be built very
small and can supply small currents for small projects. The major
downfall of this supply is that it is not isolated from the AC line and
can only supply small currents.


Schematic for Transformerless Power Supply


Total Qty.
C1 1 0.39uF 250V Capacitor
C2 1 220uF 25V Electrolytic Capacitor
D1 1 1N4741 11V Zener Diode (See Notes)
BR1 1 1 Amp 200V Bridge Rectifier
MISC 1 Line Cord, Board, Wire, Case


  1. The value of C1 can be increased to increase the amount of
    current the circuit can supply. With the values shown, the circuit can
    supply up to about 15mA. Remember to increase the size of C2 also.

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