Abstract: A control service delivers controlled magnitude energy from a sinusoidal power source in the form of a sequence of pulses conforming to the sinusoidal envelope. A gate signal operated at a selected frequency applies gating pulses to a gating device receiving the sinusoidal power signal and applying its output to a load. The load receives, at high gate signal frequencies, substantially all energy presented in the power signal and, at lower gate signal frequencies, a selected magnitude energy taken from the sinusoidal power signal. The power applied to the load does not produce undesirable noise or radio frequency interference and does not require use of an expensive, heavy and volumous choke or inductor.

Abstract: A dimmer control circuit for application to a load bank produces a sinusoidal power wave form exhibiting the desirable characteristic of suitable rise and fall times producing little or no audible or radio frequency interference. A pair of MOS-FET power devices operate in a linear mode and attenuate respective half-cycles of a single phase power line as a function of a dimmer control signal applied thereto. The device includes a mechanism for avoiding damage to the power MOS-FET by controlling conditions under which a signal change is applied to the gates of the MOSFETs, and by imbalanced attenuation between the MOS-FETs through the range of the dimmer control signal.

Abstract: A solid state relay includes a protective input stage at its control terminals to isolate the control circuit from line voltage or line current in the event of relay failure. The protective circuit includes a series combination of a voltage responsive element and a current responsive element. The current responsive element connects to the input or control terminal of the solid state relay and the voltage responsive element connects to ground. The interconnection of the current responsive element and voltage responsive element serves as the device input terminal for connection to a control circuit. In the event of relay failure, the voltage responsive element reacts to the increased voltage by providing conductivity, by way of the current responsive element, between the solid state relay input terminal and ground.

Abstract: A circuit for controlling power delivery to different AC inductive loads, which loads create different respective lag angles between applied voltage and delivered current up to a known maximum lag angle. Included is a switching circuit, typically including silicon-controlled rectifiers, connected to the load. The switching circuit is trigger-pulse-switched into conduction, and thereafter maintained in conduction so long as current through the load exceeds a certain minimum value. Additionally, a trigger-pulse generator connected to the switching circuit operates in two modes. In one mode, the conduction angle is less than a predetermined maximum width which is no less than the maximum lag angle. In this mode, a pulse is generated whose width is essentially equal to the conduction angle. In the other mode, the conduction angle is no less than the maximum width, and the generated pulse has a fixed width substantially equaling the maximum width.

Abstract: A stored-cue lighting-control system for controlling the illumination of a selected space, such as a stage. The system includes a photodetector for following the level of illumination in the space. During storing of cue data associated with a particular cue, related data, regarding the level of illumination intended to be produced by the cue, is also stored. During functioning of the system to place different successive cues in the space, the stored illumination level data is compared with current real-time data reflecting the actual illumination level then being produced in the space. An indicator signals any difference noted as a result of this comparison.