This empty outlet of an electric cord plugged in to an outlet can induce 60 Hz powerline distortion in the AD620 and OP490 circuit (isolated with a battery) located 6 inches away.
I can't detect any magnetic field around the outlet, at least not more than 0.2 milligauss (which is the background field of the Trifield meter.)
How do you compute the electric field of this empty outlet 6 inches away? Whatever the value, no matter how miniscule, it can indeed trigger distortion in the 20,000 gain op amps. Is this really possible?
If the electromagnetic field from 60 Hz powerline is only say 0.01 milligauss and undetectable by conventional EMF meter, can it still affect op-amps? The gain of an op-amp can be 20,000 times. Does this mean the 0.01 milligauss power line frequency also got amplified, or is it not EMF related but capacitance related or others?
Please share how to compute what happens if 0.01 milligauss got amplified by 20,000 too, if you know how (if this is how it works where the 0.01 milligauss got amplifed by the op-amps.)