Europhysics News (2001) Vol. 32 No. 4
Physics... in action
Dr. Vassilis Lembessis, The University of Southeastern Europe, Athens
The electric guitar is the one instrument that epitomises rock music. As with so many other ear-shattering inventions, physics played its part.
Thus the operation of the electric guitar is radically different from that of the acoustic. Whereas in the acoustic guitar the sound depends on the acoustic resonance produced in the hollow body of the instrument by the oscillations of the strings, the electric guitar is a solid instrument, so there is no resonance. Instead the oscillations of the metal strings are sensed by electric pickups that send signals to an amplifier and a set of speakers. As the string oscillates toward and away from the coil, the induced current changes direction at the same frequency as the string’s oscillations, thus relaying the frequency of oscillation to the amplifier and speaker.
It was Jimmy Hendrix who first understood the electric guitar as an electronic instrument and who showed that we could gain further control over the music by changing the number of turns of the solenoid and thus the amount of electro magnetic flux induced in the coils and therefore their relative sensitivity to string vibrations.
Copyright EPS and EDP Sciences, 2001