Granted Patent
Utility
US 4,289,999 · App. 06/038,951
Digital variable voltage level control circuit with automatic return to neutral
Inventor:
Robert P. Harshberger, Jr.
Patented Case
View Patent ↗
Granted: Sep 15, 1981
Filed: May 14, 1979
Inventor
Robert P. Harshberger, Jr.
Assignee (at issue)
Ampex Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.