0 any musical instrument in which sound is produced mainly by means of electricity:
Keyboards are integral to many aerophones (eg the accordion), chordophones (eg the piano), and electrophones (eg the synthesizer).
The electrophone was not in the original Hornbostel-Sachs scheme of musical instruments published in 1914.
In an electrophone, the sound may be generated by mechanical or electronic oscillators (eg a synthesizer), or by acoustically generated vibrations that require electrical amplification (eg the electric guitar).
A fifth class of musical instrument has been added: electrophones, in which the sound is produced by electromagnets, oscillators, or other non-acoustic devices.
It can be debated whether the pipe organ (which uses electric key action to control solenoid valves) is an electrophone or an aerophone.
