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Making A Transformerless Power Supply


Upon surfing the net, I have found this site: displaying their projects on making a Transformerless Power Supply with a 12 volts output voltage and a current of 100mA. We usually see this kind of power supply on a China made model of rechargeable products like flashlights and mosquito killer. This circuit catches my attention because of its application in our work which needs a power supply and we can also use this power low current circuits like some of our projects that don’t needs too much power requirements.


Transformerless power supply



Schematic Diagram of Transformerless Power Supply

[ Photo credits to: ]

Note: “Be careful, this circuit is not isolated from 220 volts AC. It needs some extra care in handling this kind of supply. Dangerous High Voltage AC.”

Posted by Ronelex 6 Responses

6 Responses to “Making A Transformerless Power Supply”

  1. andrew says:

    What if i change d1-d4 in a high power diode

    • jhorapalok says:

      Changing d1-d4 to a high power diode will not change the current, the current depends on capacitor c1. However, you can use two cap in parallel in place of c1 to double the courrent from 100 mA to 200mA.

  2. Hamid Hussain says:

    i have liked your circuit diagram but can you please tell me about the capacitor c1 description was it electrolyte or ceramic

  3. Hamid Hussain says:

    purpose of zener diode why not use 12v zener instead of 15 v any reason

    • kartonics says:

      the reason may be because he assumed a zener diode with a negative-temperature coefficient (NTC) where voltage decreases as temperature increases. i might as well suggest to use a 12.8V zener.

  4. Dokta Brown says:

    It is making a noise when turn on front power switch


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