A primary load, such as a conventional household light bulb, is series connected to a power source. The conventional light switch is replaced by a series connected circuit to the source and lamp. The circuit has an energy storage capacitor and a diode. A secondary load, such as an alarm, is coupled across...http://www.google.com/patents/US4290057?utm_source=gb-gplus-sharePatent US4290057 - Sequential power distribution circuit
