Marker text: PIONEER ELECTRONICS RESEARCH LABORATORY - This is the original site of the laboratory and factory of Federal Telegraph Company, founded in 1909 by Cyril F. Elwell. Here, Dr. Lee de Forest, inventor of the three-element radio vacuum tube, devised the first vacuum tube amplifier and oscillator in 1911-13. Worldwide developments based on this research led to modern radio communication, television, and the electronics age.
California Registered Historical Landmark No. 836
Plaque placed by the State Department of Parks and Recreation in cooperation with the City of Palo Alto and the Palo Alto Historical Association, May 2, 1970