A bidirectional switch is switched so as to conduct and interrupt a bidirectional current between a pair of input terminals. A power supply is electrically connected between the pair of input terminals and produces control power by electric power from an AC power supply. A controller receives the control power from the power supply to be activated. The controller causes the bidirectional switch to be in an off-state from a start point of a half cycle of AC voltage to a first time point when a first time period elapses. The controller causes the bidirectional switch to be in an on-state from the first time point to a second time point when a second time period according to the dimming level elapses. The controller causes the bidirectional switch to be in an off-state from the second time point to an end point of the half cycle.

A dimmable induction RF fluorescent lamp comprising a dimming circuit enabling the induction RF fluorescent lamp to dim in response to a signal from an external dimming circuit, and having a main mercury amalgam having a vapor pressure at room temperature which is higher than the vapor pressure of the mercury amalgam formed on the flag.

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.

A dimming switch system (130). The system (130) may include a dimming switch (520), a weak current module (510) and a strong current module (530). The weak current module (510) may receive at least one drive signal and control a state of the dimming switch (520) based on the drive signal. The strong current module (530) may be connected to the dimming switch (520) and at least one lighting device (140). The strong current module (530) may control brightness of the lighting device (140) connected thereto based on the state of the dimming switch (520). The dimming switch (520) may include a phase-cutting switch (610) and at least one omnidirectional conduction unit (620). When the omnidirectional conduction unit (620) works, the dimming switch (520) is omnidirectionally conductive.

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 RF fluorescent lamp, comprising a bulbous vitreous portion of the RF fluorescent lamp comprising a vitreous envelope filled with a working gas mixture, a power coupler to induce an alternating electric field within the vitreous envelope, an electronic ballast, and a mercury amalgam accommodating structure mounted within the lamp envelope and adapted to absorb power from the electric field to rapidly heat and vaporize an amalgam of mercury to rapidly illuminate the lamp envelope during a turn-on phase of the RF fluorescent lamp, wherein the structure is comprised of a substrate material coated with a mixture of indium and gold.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

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.

A load control device for controlling power delivered from an AC power source to an electrical load may have a closed-loop gate drive circuit for controlling a semiconductor switch of a controllably conductive device. The controllably conductive device may be coupled in series between the source and the load. The gate drive circuit may generate a target signal in response to a control circuit. The gate drive circuit may shape the target signal over a period of time and may increase the target signal to a predetermined level after the period of time. The gate drive circuit may receive a feedback signal that indicates a magnitude of a load current conducted through the semiconductor switch. The gate drive circuit may generate a gate control signal in response to the target signal and the feedback signal, and render the semiconductor switch conductive and non-conductive in response to the gate control signal.

A method for generating a stable direct current signal, a silicon controlled switch dimming method and device, the silicon controlled switch dimming method comprising: adjusting a phase angle of a silicon controlled switch and outputting an alternating current signal related to the phase angle of the silicon controlled switch (S101); rectifying the alternating current signal (S102); converting the rectified electric signal into a steady direct current signal one-to-one corresponding to the phase angle of the silicon controlled switch, and the stable direct current signal decreases as the phase angle of a silicon controlled switch increases (S103); controlling turning on or off of an output current regulating circuit according to the magnitude of the stable direct current signal so as to control the plurality of serially connected LED lamp groups to be turned all on or all off (S104). The generated stable DC signal one-to-one corresponds to the phase angle of the silicon controlled switch and decreases with the increase of the phase angle of the silicon controlled switch. The stable direct current signal can control work status of the plurality of LED lamp groups connected in series, thereby making the plurality of LED lamp groups connected in series be turned all on or all off.