Battery-operated electrical device e.g. tooth-brush, screwdriver, torch - has battery charge sensor preventing total drainage of sec. cell battery

摘要

A sensor (8) responds to the battery charging mode to allow the ON-OFF switch (10) for the electrical device to be moved into the OFF position or to be held in the OFF position, via an intermediate electronic control stage (9). - Pref. the sensor also activates a display light (11) indicating battery recharging. A magnetic field sensor, a charging current sensor, or an AC frequency sensor is used.