Electric guitar, or as it is called a "rock guitar" was not invented in a single day. Rock guitar has come a long way of evolution from an acoustic guitar to the instrument that we see today. Although it is fair to note that this path is not over, and electric guitar still continues to change, in contrast to his sister's acoustic, which remains unchanged for many centuries. And there was an electric guitar completely by accident, as a result of experiments with the acoustic in the 30s and 40s. Inventors and revolutionaries were jazz guitarists, who were trying to find a way to "break" through the roar of trumpets and roll of drums. The soft sound of the instrument and the chamber was not suitable for large scenes. Some began to play the banjo, which had the sharper and sharper sound and more suited for playing while standing. However, the banjo sounds lost in the depth and richness guitar which is due at the last big case.
Then jazz guitarists decided to think of something to increase its volume. It all started with a move towards more high-profile steel strings, which have been used instead of nylon, but it was not enough. Then, before the guitarist began to put a microphone in front of a vocalist. But the microphone is amplified not only guitar, but all around you. And who will be engaged in framing mic of some lost in the rhythm guitarist group, when all the audience's attention is focused on standing in the middle of a scene in the rays of spotlights vocalist? And then someone (the history is unknown who) put the thought of electromagnet, which is also part of the microphone, directly under the strings, and from it to transmit a signal to the amplifier. Because the strings are metal, and not just metal, and are made of magnetic metals, with sound vibrating strings began to act as an electrical signal from the pickup on the cable connected to a portable amplifier and then to the column.