Parts of the electric guitar
The machine heads, otherwise known as tuning pegs, are used to tune the guitar by adjusting the tension of the strings. The tighter the string the higher the note.
The neck is attached to the body of the guitar and runs parallel to the strings. Pressing the strings at different points on the neck allows you to change the note of a string by changing the length that actually vibrates.
The nut marks one end of the section of the string that vibrates when you strike it. The distance between the nut and the bridge is important. The relative distance between this and each of the frets makes the guitar in tune all the way up the neck.
The frets divide the distance between the nut and the bridge following a specific mathematical formula, so that pressing the string between frets makes as precise note as possible all the way up the neck.
The bridge marks the other end of the vibrating part of the strings. The bridge has small screws which allow you to adjust the distance between it and the nut, making small changes to the intonation of the guitar so that it is in tune all the way up the neck.
The pickups convert the sound of the strings to an electronic signal which can be sent to an amplifier. There will usually be one, two or three pickups. The ones nearer the neck will give a mellow tone and the ones nearer the bridge will give a brighter tone.
The pickup switch allows you to change which pickup is sending the signal. Usually you can choose either one pickup or two together.
Tone and Volume Pots
The tone pots adjust the amount of treble in the signal. The volume pots do the same for the volume for each pickup.
The output jack is where you put the lead, which goes from the guitar to the amplifier, sometimes with effects in between.