An electronic musical instrument a musical instrument that produces or modifies sound using electronic circuitry, as opposed to acoustic musical instruments, which produce sound solely by mechanical means. Some such instruments are actually hybrids, such as electric guitars, which generate sound by mechanical means but then modify it electronically. Others, are purely electronic, such as electric organs, theremins, electronic drum kits, and synthesizers.
The origins of electronic instruments can be traced back to the eighteenth century, when attempts were made to produce music using the newly discovered phenomenon of electricity. However, it was not until the twentieth century that they developed rapidly and became nearly ubiquitous as a result of continuing advances in semiconductors and other areas of electronics. Electronic instruments have had major effects on the development of music, mainly popular music and so-called contemporary classical music, including allowing a wider range of sounds to be produced and simplifying composing and performing by eliminating the need for costly and difficult-to-play acoustic instruments. The big exception is classical music, which has mostly resisted inroads by electronic instruments, largely because it was originally composed for acoustic instruments and also because many of its devotees prefer the sound of acoustic instruments to that of electronic instruments.