A method and apparatus for extracting power in a switch location, and in a load location for use in a pre-existing infrastructure of switching AC power to a lamp (or other load) via a two terminal switch device. The switch is replaced with a module including a first controlled switch (such as a triac or relay) and a first impedance (such as a capacitor) connected in parallel, and another module including a second controlled switch (such as a triac or relay) and a second impedance (such as a capacitor) connected in parallel, is installed at the load location. In an off state where the two controlled switches are in open state, current is flowing via the impedances, but not through the load, so that power extractor circuits in the modules, connected in series to the impedances, extract low power for DC powering logic and other loads in the modules.

A discharge lamp lighting apparatus is provided with a pulse generation part, and a power supply part converts DC applied voltage into alternating current corresponding to a frequency of the pulse, and supplies the alternating current to the discharge lamp. The pulse generation part is structured to alternately output a first pulse and a second pulse that has a lower frequency than the first pulse. The frequency of the second pulse is set to a predetermined reference frequency when a value of the applied voltage coincides with a predetermined reference value, is set to a lower frequency than the reference frequency when the value of the applied voltage exceeds the reference value, and is set to a frequency that is equal to or lower than the reference frequency when the value of the applied voltage falls below the reference value.

An LED driver circuit includes a primary circuit and a circuit electrically isolated from the primary circuit, a transformer having a primary winding configured to receive power from an alternating current source and to generate power in a first secondary winding configured to provide power to the electrically isolated circuit, and to generate power in a second secondary winding configured to provide power to the primary circuit, and a conductor connected to an end of the first secondary winding and configured to connect a winding driver signal to the first secondary winding to generate power in the second secondary winding.

The present invention includes a welding system that has at least two metal inert gas (MIG) welders configured to perform a cooperative pulsed MIG welding process. The welding system also includes at least one communications link connecting the at least two MIG welders to deliver at least one of subordination commands and superiority commands to either of the at least two MIG welders to synchronize the cooperative pulsed MIG welding process.

In embodiments, improved capabilities are described for dimming performance of lighting methods and systems, such as the improvement of dimming LED lamps that are dimmed from standard external dimming devices. Methods and systems for improving dimming performance include a fast startup override facility for overriding a default dimming function of the lamp's electronics through forcing the lamp electronics to operate with a higher than normal duty cycle to ensure the lamp electronics can deliver higher than normal power to an LED module during a dimming current level startup condition. Dimming facilities may also include a dynamic RC selection facility, an active N-level bleeder facility, a dimmer-type detection facility, an improved dimming linearity through symmetrical phase cutting facility, and a flicker reduction facility.

A system provides post-match control of microwaves in a radial waveguide. The system includes the radial waveguide, and a signal generator that provides first and second microwave signals that have a common frequency. The signal generator adjusts a phase offset between the first and second signals in response to a correction signal. The system also includes first and second electronics sets, each of which amplifies a respective one of the first and second microwave signals. The system transmits the amplified, first and second microwave signals into the radial waveguide, and matches an impedance of the amplified microwave signals to an impedance presented by the waveguide. The system also includes at least two monitoring antennas disposed within the waveguide. A signal controller receives analog signals from the monitoring antennas, determines the digital correction signal based at least on the analog signals, and transmits the correction signal to the signal generator.

A discharge lamp driving device includes: a discharge lamp driving unit which supplies drive power to a discharge lamp; and a control unit which controls the discharge lamp driving unit according to a waveform of the drive power. The waveform has n launching periods and a low-power mode lighting period. The n launching periods include a first launching period in which the drive power increases toward refresh power that is equal to or above drive power in a low-power mode and equal to or below rated power, and (n1) launching periods in which the drive power is maintained at the refresh power. The control unit, in an x-th launching period, supplies the discharge lamp with a drive current having a drive frequency equal to or below a drive frequency of a drive current supplied to the discharge lamp in an (x1)th launching period.

The lighting device of one aspect according to the present disclosure calculates, based on a voltage value of an AC voltage applied to a discharge lamp and a current value of AC current flowing through the discharge lamp, a first power value defined as a value of power supplied to the discharge lamp in a first half period of the AC voltage and a second power value defined as a value of power supplied to the discharge lamp in a second half period of the AC voltage. The lighting device determines that a ground fault has occurred, when an imbalance state in which a difference between the first power value and the second power value is equal to or greater than a threshold value continues for a predetermined time period.

A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a pair of cathode electrode and anode electrode for main discharge is arranged to face each other, comprises a starter for generating dielectric breakdown in the electric discharge container of a discharge lamp, and a power supply circuit for supplying discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit for modulating the magnitude of current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and wherein the output current modulation circuit controls speed of change so as to be 2.6 A or less per millisecond in case the magnitude of the lamp current per square millimeter in a cross section of the cathode electrode decreases.

A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a pair of cathode electrode and anode electrode for main discharge is arranged to face each other, comprises a starter for generating dielectric breakdown in the electric discharge container of a discharge lamp, and a power supply circuit for supplying discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit for modulating the magnitude of current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and wherein the output current modulation circuit controls speed of change so as to be 2.6 A or less per millisecond in case the magnitude of the lamp current per square millimeter in a cross section of the cathode electrode decreases.