This is one of four PCBs which combine to make a smart "charging box" for inductively charging the batteries in Navlight Punches. (The punches are used for recording visits by people to specific locations in Orienteering, Rogaining etc.)

This board is the "bottom board" which sits underneath and separated from the Smart Charge TOP board, which is the main inductive charging circuit. When the punches sit inverted in the charge box, a receiving charge coil inside the punch collects energy and charges the battery at ~ 20 mA. This bottom board touches the end of the punch where another inductor PCB inside the punch can energize this circuit, to send data.

This circuit is unlikely to be of use to anyone except organizations which use the Navlight system, but is available to anyone.