An electric guitar is a guitar that uses a pickup to convert the vibration of its strings—which are typically made of steel, and which occurs when a guitarist strums, plucks or fingerpicks the strings—into electrical signals. The vibrations of the strings are sensed by a pickup, of which the most common type is the magnetic pickup, which uses the principle of direct electromagnetic induction. The signal generated by an electric guitar is too weak to drive a loudspeaker, so it is plugged into a guitar amplifier before being sent to a loudspeaker, which makes a sound loud enough to hear. The output of an electric guitar is an electric signal, and the signal can easily be altered by electronic circuits to add “color” to the sound or change the sound. Often the signal is modified using effects such as reverb and distortion and “overdrive”, with the growling sound of the latter being a key element of the sound of the electric guitar as it is used in blues and rock music.
Invented in 1931, the amplified electric guitar was adopted by jazz guitarists, who sought to be able to do single-note guitar solos in large big band ensembles. Early proponents of the electric guitar on record included Les Paul, Lonnie Johnson, Sister Rosetta Tharpe, T-Bone Walker, and Charlie Christian. During the 1950s and 1960s, the electric guitar became the most important instrument in pop music. It has evolved into an instrument that is capable of a multitude of sounds and styles in genres ranging from pop and rock to country music, blues and jazz. It served as a major component in the development of electric blues, rock and roll, rock music, heavy metal music and many other genres of music.