Position-sensing circuit
First Claim
1. A bistable position-sensing circuit comprising:
- (a) an elongated first electrically-conductive element having first and second segments,(b) a second electrically-conductive element, movable along the length of said first element, while maintaining electrical contact with said first segment, said second segment, or both segments,(c) a first energy-storage element electrically connected to said second element, and(d) a second energy-storage element electrically connected to said first segment and to said first energy-storage element,whereby a time constant of said circuit undergoes a step-wise change when said second element is positioned to contact both segments of said first element.
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Accused Products
Abstract
A position-sensing circuit includes an elongated electrically-conductive element divided into two elongated segments. A conductor moves along the element, maintaining electrical contact with at least one of the segments. A first capacitor is connected to the conductor and a second capacitor is connected to one of the segments. When the conductor bridges a gap between the segments, a step-wise change in the time constant of the circuit results. This step-wise change precisely and reproducibly indicates the position of the conductor as being across the gap. The circuit finds particular advantage in a three-way dimming system that permits a remote switch to provide power to a load even if a dimmer that controls the load has been set to provide minimum or no power to the load.
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Citations
15 Claims
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1. A bistable position-sensing circuit comprising:
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(a) an elongated first electrically-conductive element having first and second segments, (b) a second electrically-conductive element, movable along the length of said first element, while maintaining electrical contact with said first segment, said second segment, or both segments, (c) a first energy-storage element electrically connected to said second element, and (d) a second energy-storage element electrically connected to said first segment and to said first energy-storage element, whereby a time constant of said circuit undergoes a step-wise change when said second element is positioned to contact both segments of said first element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for controlling electrical power to a load comprising, in combination:
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(a) a phase-control dimming system to control power to said load in accordance with a signal provided by a control circuit, which includes a potentiometer positionable for determining the value of said control signal, said potentiometer comprising (i) an elongated resistive element, having first and second segments, and (ii) a wiper that is movable along the length of said resistive element, while maintaining electrical contact with said first segment, said second segment, or both segments; (b) a first capacitor electrically connected to said wiper and to a second capacitor, said second capacitor being electrically connected to said first segment of said resistive element and to an override resistor, whose resistance is less than the resistance of said second segment, whereby, when said wiper is moved along said second segment to contact both segments of said resistive element, a time constant of said control circuit undergoes a step-wise increase, thereby turning off power to said load; and (c) a first switch means, which (i) if power to said load is on, turns said power off, and (ii) if power to said load is off, turns said power on to a value determined either by said potentiometer position or by the value of said override resistor. - View Dependent Claims (12, 13, 14, 15)
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Specification