Acoustic guitars use the hollow resonating chamber of the body of the guitar to amplify and resonate the sound of the strings being plucked, but on an electric guitar, this isn't the case. The body of an electric guitar is usually entirely solid, and the sound of the strings being struck is picked up by something called a pickup, which basically measures the amount of vibration of a particular string, and transmits this frequency to an amplifier. The amplifier then magnifies this frequency to create a sound which is not only audible, but also usually modified or distorted in some way to create the distinctive sound of an electric guitar. Without a pickup or an amplifier, the sound of an electric guitar is less than impressive, and is by no means merely a quieter version of what you would hear with an amplifier.

The pickups work by detecting the amount of vibration of a string, because the amount of vibration is directly equivalent to the frequency, and it is the frequency of a string's vibration that generates the note. By holding a string down against one of the frets on the fret board or neck of the guitar, the length of the string is reduced, and as a result, the string's natural vibration of frequency is changed, and this in turn affects the note. There are different types of pickup that work in slightly different ways, but the most commonly found variety is an electromagnet. The electromagnetic pickups are bundles of copper wire wound very tightly into a small coil, and these are then positioned right underneath the strings. When the string is struck, it moves, and this generates a very small electric field measurable in volts, and this voltage is the signal which is sent to the amplifier.

Effectively such electromagnetic pickups work in the same way as an electric generator. These coils of copper wires are either found as single coils or as doubles, with the advantage being that double coil pickups are less likely to pick up noise from other nearby electric fields. In the 1950s the double coil humbucker was developed, and this used two separate copper coils, with one placed in the opposite polarity of the other, and this effectively cancelled out any problem as far as stray electrical field noise was concerned. These double coil humbuckers do create a different sound and tone to the single coil pickups, generally considered to be a much heavier sound, whereas the single coil pickups are used by those players looking for a much brighter sound, and usually with a much broader range.

Today the style of pickup is generally tailored to suit the type of sound that the player wants to try to achieve, and the general rule of thumb is that the smaller the amount of copper wire used in the coil, the brighter the sound, whereas the more coils used, and the more wire used in the pickup, the heavier the overall sound will be. There are also sometimes options to have the coil wired for extra switching, so that effects can be achieved by altering the way the coil works, and thereby changing the sound of the note dynamically. These effects usually require the guitar to have battery power to achieve the changes.

Although double coil pickups are usually the maximum, there are exceptions, and the Fender Stratocaster is one very well known example. The Fender Stratocaster actually uses three coil pickups, and this is what gives this particular model of guitar such a distinctive tone. In complete contrast, there are also piezoelectric pickups which use crystals positioned under each string, and when the string is struck, its vibrations very slightly alter the shape of the crystal. As the crystal changes shape, a very small voltage of electricity is produced, and by amplifying this, the sound is achieved.

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About the Author

Victor Epand is an expert consultant for electric guitars, humbuckers and Fender Stratocasters. You can find the best marketplace at these sites for electric guitars, humbuckers and Fender Stratocasters, sheet music, guitar tab, and home theater audio.