System for determining periodic values of phase angle of waveform power input including voltage detector for detecting periodic values of average voltage of waveform power input and detecting corresponding periodic values of peak voltage of waveform power input. System also includes phase angle detector in signal communication for receiving periodic values of average voltage and peak voltage from voltage detector. Phase angle detector also detects periodic values each being ratio of one of periodic values of average voltage divided by corresponding periodic value of peak voltage, or being ratio of peak voltage divided by average voltage; and determines periodic values of phase angle of waveform power input corresponding to periodic values of ratio. Lighting systems.

A circuit adapted to detect applied voltage and/or voltage based conditions. The circuit comprises a zero-cross detection circuit and a controller. The zero-cross detection circuit is adapted to output a zero-cross signal comprising zero-cross events based on an applied alternating current power signal. The controller is adapted to store a relationship between a pulse width delta, frequency, and voltage. The controller is adapted to sense the zero-cross signal from the zero-cross detection circuit to determine its frequency and pulse width delta by calculating a difference between a high-time and a low-time of the zero-cross signal, and determine the applied voltage based on the stored relationship. The controller can adjust at least one setting of the circuit based on the determined applied voltage, such as the timing of a dimming circuit. In another embodiment, the controller may directly detect voltage based conditions, such as zero-cross delays a dimmer circuit. The controller is adapted store a relationship between a pulse width delta and zero-cross signal delay. The controller is adapted to receive the zero-cross signal from the zero-cross detection circuit, determine a pulse width delta, and determine a zero-cross delay based on the determined pulse width delta and the stored relationship.

A technology for configuring a lifestyle LED light with a tunable light color temperature is disclosed. The technology of tuning the light color temperature is made possible by blending two LED loads emitting light with different color temperatures thru a light diffuser with an arrangement that a first electric power delivered to a first LED load emitting light with a low color temperature and a second electric power delivered to a second LED load emitting light with a high color temperature are reversely and complementarily adjusted for tuning a diffused light color temperature such that a total light intensity generated by the LED light is kept essentially unchanged.

Systems and methods for dimming control using TRIAC dimmers are provided. An example apparatus for a power conversion system includes: a process-and-drive component configured to receive an input signal and output a drive signal to a switch to affect a current that flows through a primary winding of a power conversion system. The input signal includes a first pulse associated with a first input period and a second pulse associated with a second input period. The drive signal is associated with a first modulation period for the first input period and a second modulation period for the second input period. The process-and-drive component is further configured to: determine the first modulation period for the first input period; change the drive signal between a first logic level and a second logic level at a modulation frequency during the first modulation period; determine the second modulation period for the second input period.

The present invention is directed to an electrical wiring device that includes a housing assembly having a plurality of terminals at least partially disposed therein, the plurality of terminals being configured to be coupled to an AC power source and at least one electrical load, the plurality of terminals being configured to provide the electrical wiring device with regulated AC power in a device energized state. At least one variable control mechanism is coupled to the housing assembly, the at least one variable control mechanism being configured to regulate power to the at least one electrical load by way of a control knob being user settable between a first adjustment stop and a second adjustment stop. A user accessible calibration button is included. At least one series pass element coupled to the at least one variable control mechanism, the at least one series pass element being configured to provide load power to the at least one electrical load in accordance with a user setting of the control knob. A regulation circuit is coupled to the user accessible calibration button and the at least one series pass element, the regulation circuit being configured to enter a calibration mode when the control knob is at or near the first adjustment stop or the second adjustment stop and the user manually actuates the calibration button, the regulation circuit establishing at least one pre-determined load power setting when the calibration button is actuated when the regulation circuit is in the calibration mode.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

[Object] To propose a control apparatus, a control system and a control method which are capable of causing another light source to adaptively emit light at a timing at which light emitted from one light source changes. [Solution] A control apparatus including: a light source control unit configured to control light emission of a second light source on the basis of profile of light emitted from a first light source and a synchronization signal for synchronizing a timing between the first light source and the second light source for radiating light on a surgical region.

A load control device for controlling the power delivered from an AC power source to an electrical load includes a thyristor, a gate coupling circuit for conducting a gate current through a gate of the thyristor, and a control circuit for controlling the gate coupling circuit to conduct the gate current through a first current path to render the thyristor conductive at a firing time during a half cycle. The gate coupling circuit is able to conduct the gate current through the first current path again after the firing time, but the gate current is not able to be conducted through the gate from a transition time before the end of the half-cycle until approximately the end of the half-cycle. The load current is able to be conducted through a second current path to the electrical load after the transition time until approximately the end of the half-cycle.

A two-level LED security light includes an LED load and a motion sensor. The LED load is activated at dusk and deactivated at dawn by a light sensing control unit. At night, the LED load is activated for performing a low level illumination to provide an evening aesthetic and a navigation capacity. When the motion sensor detects any intrusion, the LED load is switched from the low level illumination to a high level illumination for a short duration adjustable by a time setting unit and then returns to the low level illumination. The LED load is configured with one or a plurality of LEDs accommodating to a power source, wherein a voltage V across each LED is confined in a range V.sub.th<V<V.sub.max with V.sub.th being a threshold voltage to turn on the LED and V.sub.max a maximum voltage to avoid damaging the LED.

A dimmer includes a processing unit structured to generate a dimming control signal, wherein in the on state the dimming control signal has a constant voltage with a low pulse a predetermined time after each zero-crossing in power flowing through the hot conductor and in the off state the dimming control signal has a constant voltage, a load control circuit structured to electrically connect between the hot conductor and the load conductor and to selectively electrically connect the hot conductor to the load conductor based on the dimming control signal, and a snubber control circuit including a snubber structured to electrically couple between the hot conductor and the load conductor, wherein the snubber control circuit is structured to activate the snubber when the dimming control signal has the on state and to deactivate the snubber when the dimming control signal has the off state.