From the original humbucking coil invented by Electro-Voice in Indiana for public address equipment, and first refined into a guitar pickup by Gibson worker Seth Lover in 1955, humbucking pickups-whether for electric guitars or electric basses-buck the hum (cancel out noise interference) normally experienced by single pickup coils.
They do that by way of series-connection, doubled coils producing opposing polarities, through small magnetic fields around instrument strings that also induce electric currents on the coils.
Customarily, the coils rest side-by-side, whether in the open or beneath metal plate covers such as the long-familiar PAF pickups (literally: patent applied for; Gibson got the patent but the name stuck) on Gibson Les Paul and SG solid body electric guitars.
These pickups are renowned for providing a warmer, fatter tone than the single-coil pickup provides.
Alternatively, the humbucker coils can be stacked one above the other-as Fender does with some of their Stratocaster and Telecaster guitars.
Seth Lover designed the first such Fender pickup, the Wide Range, later in the 1950s.
Fender has also used standard, open-mount double-coils as the bridge pickups for some Stratocaster models; or, standard but covered double-coils as the neck pickups for some Telecaster models.
Other humbucking pickups include the Gibson Mini-Humbucker, essentially a smaller and more slender variant of the PAF style; the Gretsch Filter-Tron, born in 1957 and a standard feature on its famous Country Gentleman and other hollow body instruments; the Fender split, developed for the Precision Bass and using one stacked coil beneath the E and A strings and the second beneath the D and G strings; the Seymour Duncan SH4, an exposed double-coil the company is thought first to have designed for guitarist Jeff Beck; and, the Duncan SH-1, basically a variant of the original Seth Lover PAF and first designed to fit the 1959 Les Paul.