how i can generate 0 200mV dc using Arduino and digital potentiometer.
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you should make proper circuit and upload well programmed sketch
@nitya_123
Which Arduino do you have?
Make a voltage divider where the potentiometer is the bottom resistor.
(Note that the pot itself is a variable voltage divider but it can go up to the full applied voltage.)
Depending on how much current you need, you might need to add an op-amp or other amplifier.