This circuit was found in Maxim's documentation from the 90's. The configuration uses components from the time but can be adapted to use modern equivalents.
This charger for small batteries was obtained from the 1982 Radio Experimenter Handbook. The...
This shield can be used both to interface microcontroller circuits or TTTL. The resistor in series...
This circuit not only indicates when the battery is on but also when it is low. The circuit is...