Multiple location dimming system

Abstract

A multiple location system is provided for controlling application of alternating-current power to a load. The system employs a triac as a power carrying device, the gate control circuit for which has been modified to include auxiliary switching. Potentiometers are disposed at various different locations for determining, responsively to the setting or positioning of an actuator, such as the slide control of a linear potentiometer, the magnitude of respective control signals substantially immediately upon setting of the actuator. The signals are mutually exclusively applied to control the triac in accordance with which of the actuators is being set. Alternatively, the control signals can be applied in accordance with which one of a series of take-command switches (one for each location) was last operated. In either case, only two wires are necessary to connect the different locations to one another. In one embodiment, the actuator controls a pair of momentary-close switches associated therewith (e.g. such as a mechanical push button switch spring loaded so as to relax except when under pressure), the switch being ganged for alternative operation such that a first of the push buttons closes and the second remains open during movement of the potentiometer control slider in one direction, the first remaining open and the second being closed during motion of the slider in the other direction. The system includes a magnetic latching relay for conferring dimming control on that potentiometer control in which closure of one of the momentary-close switches has last occurred.