Granted Patent
Utility
US 4,654,575 · App. 06/830,126
Ripple detecting polarity indicator for battery charger
Inventor:
Cordell V. Castleman
Patented Case
View Patent ↗
Granted: Mar 31, 1987
Filed: Feb 18, 1986
Inventor
Cordell V. Castleman
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.