The second transmission electron microscope (TEM) at OSU was an RCA EMU-3H. The model was commercially introduced in 1955 and remained available for about 10 years. OSU’s microscope was located in the Zoology Cordley Hall “Electron Microscopy Laboratory” in 1963-4 and remained in service until a lens power supply failed in the early 1980’s. Because RCA no longer made electron microscopes, and replacement parts could not be located, the microscope was dismantled and scraped.

RCA-EMU-3H featured selectable 50 or 100 kilovolt beam acceleration voltages, a magnification range from 1,400x to 32,000x, imaging and selected area diffraction viewing modes, and 10 Å resolution. It had vacuum-tube circuitry, manually operated vacuum system, and its camera accepted five 2”x10” glass photographic plates.