Importance

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Abstract

A time-delayed, variable light intensity control is configured to operate in a conventional mode in which the illumination level of incandescent lights is adjusted in accordance with rotation of the dimmer knob and in automatic dimming modes in which the illumination level is further dimmed over a predetermined period of time, to either a low level of illumination suitable for use as a night light, or until extinguished. The light intensity control controls the illumination levels as well as the time delay during automatic dimming by varying the phase angle at which a power triac is triggered. The phase angle is controlled by the timing of the generation of a first pulse in accordance with the rotation of the dimmer knob and the generation of a fixed period pulse which occurs one half cycle later. The control system is useful for other AC control systems.

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First Claim