PROTECTION CIRCUIT FOR BATTERY POWERED ELECTRONIC DEVICES

摘要

A rechargeable battery provides a source of operating potential for an electronic circuit load. An operator controlled on-off switch connects the battery to a relay, and through the normally open relay contacts, to the electronic circuit. The relay winding is returned to ground through a capacitor. When the switch is closed the relay is momentarily energized by the current which charges the capacitor. A transistor has its collectoremitter path in parallel with the capacitor and its base coupled to the movable top on a voltage divider connected across the load. In the absence of a low voltage condition across the load, the transistor conducts maintaining relay closure for normal circuit operation.