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# Transformerless power supply circuit design electronic project

A very simple transformerless power supply electronic project which require few electronic components can be designed very simple using this circuit diagram .

We can observe that the U2 tension of this transformerless power supply circuit project it's equal with the zenner diode voltage and it's kept at this value such a long time than the output current .

We can calculate the value of components of these power supply circuit using these formulas .

I2=120C1(220-0.4U2).

C1=I2/1209220-0.4U2)

C1 in UF,I2 in mA ,u2 in V)

C1 capacitor must be a high quality capacitor witch can support a 400 V DC or 250 V AC.The resistor witch is used for short circuit protection must be equal with 3/I2.

C2 must have a value (in uf) equal with : C2=200I2/U2 (I2 in mA,U2 in V).

Zenner diode mast have a power equal with I2U2 and and must support values for current and voltage equal with I2 and U2.

With a small volume and low consumption , shortcircuit protection this power supply allow to obtain a low power and economic supply.

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