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.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

An 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. When a motion signal is detected by the motion sensor, the LED load is switched to perform a high level illumination for a short time period and then resumes to the low level illumination. The low level illumination and the high level illumination are respectively adjustable within respective designed ranges. The LED load is driven by a switching circuitry comprising a driver to output an adequate voltage with constant electric current such that 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 and V.sub.max being a maximum voltage avoiding damaging the LED.

A method of configuring a white LED light with a tunable diffused light color temperature, includes using a light-emitting unit configured with a first LED load emitting light with a first color temperature between 1800K and 3000K and a second LED load emitting light with a second color temperature between 4000K and 6500K, electrically connected in parallel; using a light diffuser to cover the first LED load and the second LED load to create a diffused light with a diffused light color temperature; using two semiconductor switching devices working in conjunction with a controller to respectively control a first electric power delivered to the first LED load and a second electric power delivered to the second LED load such that a total electric power of the light-emitting unit remains unchanged; and using at least one external control device to activate a selection of the diffused light color temperature.

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.

A load control device for controlling power delivered from an AC power source to an electrical load may comprise a thyristor, a gate current path, and a control circuit. The control circuit may be configured to control the gate current path to conduct a pulse of gate current through a gate terminal of the thyristor to render the thyristor conductive at a firing time during a half-cycle of the AC power source. The control circuit may operate in a first gate drive mode in which the control circuit renders the gate current path non-conductive after a pulse time period from the firing time. The control circuit may operate in a second gate drive mode in which the control circuit maintains the gate current path conductive after the pulse time period during the half-cycle.

A zero-crossing detection method, and devices incorporating the method, enable a selectively enabled bias to pull-up a zero-crossing signal, thereby enabling monitoring of the zero-crossing of both half-cycles of the alternating current (AC). This improves synchronization of the device in noisy environments and enables the detection of dimming problems during either half-cycle. Aspects can detect improper dimmer firing events on either polarity of the power cycle and restore normal dimmer operations when needed.

A linkable LED lighting system designed with an on line free setting method for adjusting operating parameters of at least one LED security light is disclosed. The linkable LED lighting system comprises at least one LED security light working in conjunction with a mobile phone loaded with an APP (software application) for controlling and setting at least one lighting characteristic of the at least one LED security light including time length settings, light intensity settings, color temperature settings, detection range settings, or signal frequency range or signal format settings for screening, accepting, and processing said wireless instruction signal(s) characterized with the same signal frequency range or the same signal format.

A mechanical switch dimming and speed regulation control system includes a double-contact mechanical switch including at least one alternating current live wire input end, and at least one group of normally closed contact and normally open contact mutually short-circuited with each other, a dimming and speed regulation controller including a signal collector and a dimming and speed regulation control circuit, and a controlled device, outputs of the normally closed and open contacts loop-connected with the dimming and speed regulation controller, the dimming and speed regulation controller loop-connected with the controlled device, the signal collector electrically connected with an output loop of the double-contact mechanical switch and the dimming and speed regulation control circuit, respectively; the dimming and speed regulation control circuit loop-connected with the controlled device. The present disclosure implements high-power dimming and speed regulation control of a single live wire by using the double-contact mechanical switch, and overcomes problems of power limitation of a conventional dimming and speed regulation switch and difficulty for an intelligent switch to implement dimming and speed regulation of the single live wire.

The disclosure is a connectivity APP loaded in a mobile phone for configuring a linkable security lighting system comprising a plurality of LED security lights installed outdoors, wherein by operating the connectivity APP the plurality of LED security lights are divided into N groups of member security lights to be linked. Each group of member security lights is assigned a group code to be applied to each member security light in the group such that within the group the member security lights are interlinked wirelessly via wireless signals prefixed with the same group code, wherein when a member security light is initiated by a sensing signal for operating an illumination mode, the member security light being initiated acts as a commander to transmit an instruction signal to activate all member security lights belonging to the same group code to synchronously operate the illumination mode.