Guitar pickups are really interesting technology. most people have seen or played an electric guitar, and the way that the guitar is able to transmit sound to the amplifier is through the pickups. in essence, a guitar pickup is a set of magnets wrapped in wire. while there are different types of pickups such as humbuckers, single coils, and p90's among others, they all operate in generally the same way. It all starts by playing a string on the guitar, and from there, the physics really gets interesting. the permanent magnets in the pickup create a magnetic field, and the vibration of the string creates a flux through the magnetic field, which then creates a voltage in the wire which is then transmitted to the amplifier via a quarter inch cable so you are actually able to hear it at a reasonable volume. Other types of pickups such as humbuckers, offer specific benefits not enjoyed by single coil pickups, Humbuckers feature 2 coils that are wound opposite eachother as well as having every other magnet have the polarity flipped so that when interference noises are picked up by the pickups, the noise is distributed evenly throughout all directions, and the interference noises are then cancelled out by the opposite wound coils since they have an equal amount of interference distributed throughout them in opposite directions. Guitar pickups are really a very influential invention, allowing new cool sounds to be made with a guitar, creating the basis for entire genres of music.