Granted Patent
Utility
US 4,820,973 · App. 07/223,697
Impedance measuring system
Inventor:
Jose A. Alvarez
Patented Case
View Patent ↗
Granted: Apr 11, 1989
Filed: Jul 22, 1988
Inventor
Jose A. Alvarez
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.