oscillograph

oscillo- +‎ -graph

oscillograph (plural oscillographs)

1. An instrument for measuring alternating or varying electric current in terms of current and voltage; an oscilloscope.
   • 2009 January 26, Dennis Hevesi, “J. Lamar Worzel, Expert on Ocean’s Depths, Dies at 89”, in New York Times‎:

     With Dr. Ewing brainstorming and Dr. Worzel leading the designers, the team slapped together precursors of more precisely manufactured measuring devices: a camera to take photos thousands of feet below the ocean’s surface, with a coffee-can lid for a flash reflector and a thick, diner-style drinking glass as its casing; a seismograph timed by a modified railroad pocket watch; an oscillograph, to record electrical changes, run by a motor from a toy electric train.