wowww thanks isr but here u have given all computer related link i need only some basic circuitry n i ll connect it to the sound card & ll trace it from the oscilloscope software , i want to do this very clearly so i need the proper
sensing device
You just need electrodes that make good electrical contact with the skin. It doesn't have to be fancy. You can use a piece of aluminum foil held down with sticky tape.
It works better if there's a thin layer of conductive gel between the foil and your skin to help it make better contact. That doesn't have to be anything special either. You could try to make some, but any salty kitchen condiment (e.g. tomato sauce) should work OK.
I just stuck my DMM probes into a jar of mustard to test it. It works fine. :grin: