Roland Digital Piano Models A electric guitar pickup is basically just like a vibrant mike coil. For many years, dynamic microphones have now been wired with the voice coil mounted on the primary of the microphone's transformer, and perhaps not referenced to ground (‘floating'). The microphone's case is usually connected to the wire guard, which is attached to the microphone amplifier's floor (see Rane's web site for more discussion).
By and big, energetic microphones are very quiet products as a result of the mix of transformer solitude and healthy, suspended sign lines throughout, in addition to shielded, humbucking coils.
So why don't you instruments? Guitars are once plagued by noise. Humbucking pickups are just a partial (though crucial!) solution. Well-known solution is to float the guitar pickup to a balanced result, as being a microphone. An identical thought was printed this 2001 patent application such as Roland Digital Piano Models?