The Hornbostel–Sachs system of musical instrument classification groups all instruments which make sound primarily by way of electrically driven oscillators. Though Sachs divided the category of electrophones into three distinct subcategories, specifying these three as:
- 51 - Electrically actuated acoustic instruments
- 52 - Electrically amplified acoustic instruments
- 53 - Instruments which primarily produce sound with electrically driven oscillators
In the present day only instruments belonging to this last subcategory are considered "electronic musical instruments".