There is a lot to say about pickups and the pickup is perhaps the most critical component of an electric guitar to define the voice. Personally , I like my guitar to have as great a range of tonal qualities as possible. When I flick a switch or turn a knob I want to hear a difference in the overall sound of the output.
Inventor George Beauchamp created the first electric guitar pickup in 1931. Pickups differ in the manner of construction, magnetic material used, gauge of wire, physical dimension of pole pieces, bobbin material, number of windings, and physical dimension of the coil. All of these factors, combine to determine the strength and shape of the magnetic field above the pole pieces and ultimately how the strings interact with the magnetic field.
It is the movement of a string through a magnetic field which indices current in the coil which eventually provides a signal to the amplifier.
most pickups use 42 to 44 gauge wire which is the thickness of fine cotton thread. Modern pickups are mostly machine wound and using very precise thickness of pure copper with a very even coating of insulation, and a precise number of evenly spaced windings. These pickups can be very uniformly produced with a predictable resistance, impedance, and known output. Older or vintage pickups tended vary a lot more and thus some pickups were hotter (more output) and more importantly the shape and strength of the magnetic field had a lot more variability.
Stratocasters generally have single coil pickups. Single coils by the nature of their construction tend to sound brighter and emphasize higher frequencies. This quality is often referred as Spank, squawk, or sparkle. Single coils also have the drawback of picking up electronic noise in the room. Things like fluorescent lamp ballasts, would produce a 60 cycle hum that could be heard at the amp.
Seth Lover invented the humbucker pickup 1955, known as the PAF ( Patent Applied For) which was used in Gibson guitars. The humbucker consisted of two coils wound in opposite directions right next to each other which had the effect of cancelling noise. But , as always there are other consequences, humbuckers sound have a higher resistance, impedance, and don’t emphasize the highs like a single coil. The PAF is responsible for the lovely warm tone you get from a Gibson Les Paul.
Musicians being the innovative, curious, and mischievous people they are are constantly messing around with their guitars trying to make them sound different. So they tried putting two singles coils together in parallel, or series, or a humbucker and a single coil, or two single coils out of phase with each other so it acts like a humbucker. Well, just about any combination you can think has been tried, and a new guitar was born. I’m not judging here, some combinations sound great and others are a little thin but I suppose you might find a need for that in some song so , cool beans.
I have the ability to wind pickups on a custom winding machine I built. It is always fun to make the pickup yourself since I have complete control over how many windings, how the windings are laid out, choice of magnets, direction of wind, and polarity.