smps i need 180v to 280 ac variable voltage to constant dc 12v ,frequency 50 Hz ,2A.

Hi i am supriya, i have a smps with 230 constant input to constant 12v dc output , frequency 50Hz, 2A. But i need variable ac input from 180 to 280 ac voltage to constant dc 12 v, i need a circuit can u plz suggest me.

Is the current measured at AC input, 230V, or at 12 V DC?
For the variable AC input from 180 to 280 V AC the best device is the "variac", mechanically adjustable AC transformer. Such devices are available for up to 100 W power.

For a "constant' DC of 12 V (what load?) you need to use a DC voltage regulator, 7812 or adjustable LM317T, with a DC input of 15...20 V



To my knowledge the commercial SMPS are mostly specified for 96 to 230 V AC, not up to 280 V.

Find a old-new type PC Power Supply Unit, they work 85-270VAC and they have multiple outputs such as +5V, +12V etc..
Cheap ( second hand is 10-20S ) and efficient....( if you don't have strict noise constraints because they may be a little bit noisy..)

But if you would construct your own power supply, NXP has very wide range PSU controllers.

Hi i need a circuit with out Transformer .



Hi i need a
circuit with out Transformer.