I would like to sense current in 230V ,500mA circuit.
How can i do that,is it possible to amplify the signal before giving to the controller or ADC

 

You don't say whether you are measuring AC or DC, but I guess from the 230V that it is AC, in which case you need a current transformer. You can buy these but they are not ridiculously cheap. A google will lead you to lots of DIY versions. A totally outrageous version is here:
http://www.instructables.com/id/2-Carabiner-split-core-AC-transducer/

 

thank you for the update.
exactly am trying to measure from AC. I would like to make a set up in my circuit itself.

 

You don't say whether you are measuring AC or DC, but I guess from the 230V that it is AC, in which case you need a current transformer. You can buy these but they are not ridiculously cheap. A google will lead you to lots of DIY versions. A totally outrageous version is here:
http://www.instructables.com/id/2-Carabiner-split-core-AC-transducer/

thank you for the update.
exactly am trying to measure from AC. I would like to make a set up in my circuit itself.

 

These are one of the best, non-invasive methods of measuring current.
AC or DC using low level logic.
http://sensing.honeywell.com/products/Current-Sensors/Open-Loop/CSLA/Ne/3025/N/3029
Max.