Humbucking pickup: This type of pickup has two single coils combined into one unit. Each coil is reverse wound so that the hum from first coil cancels the hum from the second. The two coils are wired in series so the total resistance is additive, hence producing a "hotter" and quieter pickup (if the two coils were wired in parallel, the total resistance is half the sum of the resistances of each individual coil, assuming both coils are about the same resistance). In either case (parallel or series), the hum does cancel, hence the name "Humbucking". Note the difference bewteen parallel and series wiring of pickups/coils. Parallel is why the "in-between" setting used on a Stratocaster (combining the middle pickup with the neck or bridge pickup), does not produce a Humbucking pickup sound. Also, the in-between switch setting on a Humbucking two pickup Gibson is less powerful than each pickup individually. The two Humbucking pickups are combined in parallel (even though the two coils of each pickup are in series), thus giving the average of the two pickups divided by two. Interesting, huh?