3676770 is referenced by 161 patents and cites 2 patents.

A continuously operating low dissipation system for sensing the electrical resistance of an element while the element carries a normal operating current. A pulse of electrical energy having a regulated ohm's law related first parameter is switched through the element while a second ohm's law related parameter of the element's response to the energy pulse is simultaneously measured. These two known parameters provide the information necessary to determine the element's resistance using Ohm's law. In the preferred embodiment voltage and current are used as the two parameters. The system is calibrated for the regulated level of the first parameter while the second parameter is amplified and stored in a sampling circuit for continuous display between pulses as an indication of resistance. The pulse techniques of this disclosure allow continuous operation of the system without heating of the resistive element or excessive power use. The resistance indication is additionally useful for indicating the remaining charge in a battery where the indicated resistance is the battery's internal resistance. A distinct battery terminal voltage indication is also given.

Title
Pulse sampling battery fuel gauging and resistance metering method and means
Application Number
05/037,630
Publication Number
3676770
Application Date
May 15, 1970
Publication Date
July 11, 1972
Inventor
Eby Richard L
Sharaf Harold M
Assignee
Anderson Power Products
IPC
G01n 27/46
G01R 31/36
G01R 27/02
G01R 27/20
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