This bargraph circuit is from an ancient American documentation. It indicates the charge state of a set of 4 batteries from 9.6 to 5.2 V.
If you have a common analog multimeter, you can increase its input resistance in the measurement of...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern...
August 2017 - Texas Instruments' new integrated circuit BQ25872, a 7-A keyed battery charger with...