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, and 53 = instruments in which make sound primarily by way of electrically driven oscillators, In the present day only instruments belonging to this last subcategory are considered "electronic musical instruments." List ANS synthesizer Chamberlin Mellotron Clavioline Croix Sonore Electronde Electronic drum Electronic keyboard Hammond organ Moog modular synthesizer Novachord Ondes Martenot Therevox Ondioline Oramics Radiodrum Spharophon Stylophone Synthesizer Analog synthesizer Digital synthesizer Telharmonium Theremin Electro-Theremin Trautonium Sees also List of classic synthesizers List of Hammond organs Electronic musical instruments Electronic