Automatic light-extinguishing circuit

摘要

An automatic light-extinguishing circuit (60) is disclosed for extinguishing, for example, the headlights (30) of an automobile some interval of time after the ignition switch (54) is opened. The circuit includes a temperature-actuated switch (72), switching relay (78), and diode (86). The heating element (74) of the temperature-actuated switch and a solenoid (80) of the switching relay are energized upon closure of the ignition switch, closing two normally open switch element (82 and 84). In this condition, current passes through the switch elements of the switching relay to the headlights and taillights. When the heating element causes the temperature of a switch element (76) to rise sufficiently, the switch element closes, forming an alternative path of current to the solenoid. When the ignition switch is opened, this path is maintained, ensuring continued flow of current to the headlights and taillights until the switch element cools sufficiently to open. The circuit is constructed for simplicity, economy, and substantially universal adaptability to existing vehicle electrical systems.