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Power supply without transformer

2014-11-29 05:51  
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Sometimes you need low consumption power supply. In this case you can use a power supply like (power supply without transformer) in schematic from this sheet.
What is so special on this power supply ?
This power supply don't use a transformer ( transformer less power supply ) and it's require just a few components .
We can observe that the U2 tension of this power supply without transformer 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 transformer less 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 transformerless power supply allow to obtain a low power and economic supply.

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power supply without transformer circuit diagram