Pickups

One of the most important parts that make up the sound of an electric guitar is the pickup.  The changing out of a pickup is also one of the best ways to upgrade the tone of your guitar.  These are the little modules that sit under the strings in the middle of the guitar.  They are bars of metal or ceramic wrapped with tiny wire in a plastic or metal casing.  The vibration of the strings when you play is "picked up" by the pickups.  This signal is fed through your guitar cable into the amplifier where it is amplified and run through your eq controls, etc, to come out as sound.

Although there are many pickup variations, The two main basic types are "single-coils" and "humbuckers".  Single coils are the original pickups.  They what are most commonly seen on a standard type of Stratocaster.  Look at one and you can see one row of poles that go under each string and most Strats have three.  Single coils are known to have a very clear and crisp sound.  They can be heard in all types of music.  Yet they have a "hum" which can be heard when you are not playing.

By experimentation, pickup builders found that if you wired two single coils together, the "hum" is cancelled out.  Therefore you get the term "humbucker."  Humbuckers are usually twice the width of single coils and may be open on top or under a casing.  These are more popular when using louder, distorted types of guitar tones as the hum of the single coils is even more evident when using distortion or overdrive, but are also heard in all types of music.  Humbuckers can be said to have a warmer, smoother sound usually. 

They now make combo pickups that can be switched between the two.  They also make single spaced humbuckers or wider double spaced single coils if you want to modify your guitar and need it to fit in the old space.

So when picking out an electric guitar for the first time, be aware of this difference and compare them.   Use your own ears to see which you prefer.