Abstract: A user interface for a load control device allows a user to control an operating characteristic of a load to a plurality of discrete levels. The user interface comprises an adjustment member for allowing the user to select one of the discrete levels and a linear array of status indicators for displaying the discrete level. The number of discrete levels is greater than the number of status indicators. According to a first embodiment of the present invention, either one status indicator or two consecutive status indicators are illuminated to indicate the presently selected discrete level. According to a second embodiment, a fully illuminated status indicator is surrounded by two dimly illuminated status indicators to indicate the presently selected discrete level. According to a third embodiment, a single status indicator may be illuminated to indicate one or more of the discrete levels.

Abstract: An electronic ballast for driving a gas discharge lamp includes a rectifier, a valley-fill circuit, an inverter having first and second series-connected controllably conductive switches having complementary duty cycles, a control circuit for controlling the controllably conductive switches, and an independent cat ear power supply to provide power to the ballast control circuits. The result is a ballast having substantially improved power factor, THD, and current crest factor. In a preferred embodiment, the valley-fill circuit includes an energy storage device that stores energy in response to a controllably conductive switch. In an especially preferred embodiment, the controllably conductive switch of the valley-fill circuit is also one of the switches of the inverter.

Abstract: A smart dimmer for controlling the intensity of a lighting load from a source of AC power is operable to replace one of the three-way switches in a standard three-way lighting system without the need to replace the other three-way switch with a unique accessory switch. A simple rewiring is needed in the wallbox of the remaining three-way switch. In the resulting three-way lighting system, the smart dimmer is always coupled between the lighting load and the source and the remaining three-way switch is coupled between either of the load terminals of the dimmer and an accessory terminal of the dimmer. The remaining three-way switch acts to either couple or decouple an AC voltage from the accessory terminal. The smart dimmer is operable to detect a change in the state at the accessory terminal and toggle the lighting load on or off as a result of the change in state.