A dimmer is provided for controlling power to a load, the dimmer having a ground leakage power supply deriving power from a connection of the dimmer to ground. The power supply may be a switching-mode power supply that can be the sole or primary power supply to power operation of the dimmer, including operation of the controller.

Insulating properties between a metallic member supporting a power semiconductor module and an input/output terminal of the power semiconductor module are secured. In a power conversion device in which a bus bar of a connecting member is connected to an input/output terminal and the like of a semiconductor module protruding through an opening of a metallic member, the connecting member includes extended portions which extend in a space between the bus bar and the opening of the metallic member.

Insulating properties between a metallic member supporting a power semiconductor module and an input/output terminal of the power semiconductor module are secured. In a power conversion device in which a bus bar of a connecting member is connected to an input/output terminal and the like of a semiconductor module protruding through an opening of a metallic member, the connecting member includes extended portions which extend in a space between the bus bar and the opening of the metallic member.

An electronic brushless variable transformer. Variable autotransformers, use brushes, and as such, have moving parts requiring maintenance and periodic cleaning of the brushes. A variable transformer without brushes is advantageous in that it eliminates the cleaning and maintenance of brushes.

An electronic brushless variable transformer. Variable autotransformers, use brushes, and as such, have moving parts requiring maintenance and periodic cleaning of the brushes. A variable transformer without brushes is advantageous in that it eliminates the cleaning and maintenance of brushes.

A hub device and a power supply method thereof are provided. The hub device includes a power input port, first and second power output ports, a power management circuit and a controller. When first and second electronic devices are respectively connected to the first and second power output ports, the controller determines an input electric power from at least one default supply power of the power adapter based on first operating power information of the first electronic device and second operating power information of the second electronic device, so as to control the power adapter to provide the input electric power to the power input port. The power management circuit receives the input electric power to generate first and second operating power, so as to output the first operating power to the first power output port and output the second operating power to the second power output port.

A power supply unit for use with thermostats or other like devices requiring power. A power supply unit may be designed to keep electromagnetic interference emissions at a minimum, particularly at a level that does not violate governmental regulations. A unit may be designed so that there is enough power for a triggering a switch at about a cross over point of a waveform of input power to the unit. Power for triggering may come from a storage source rather than line power to reduce emissions on the power line. Power for the storage source may be provided with power stealing. Power stealing may require switching transistors which can generate emissions. Gate signals to the transistors may be especially shaped to keep emissions from transistor switching at a minimum.

A power supply unit for use with thermostats or other like devices requiring power. A power supply unit may be designed to keep electromagnetic interference emissions at a minimum, particularly at a level that does not violate governmental regulations. A unit may be designed so that there is enough power for a triggering a switch at about a cross over point of a waveform of input power to the unit. Power for triggering may come from a storage source rather than line power to reduce emissions on the power line. Power for the storage source may be provided with power stealing. Power stealing may require switching transistors which can generate emissions. Gate signals to the transistors may be especially shaped to keep emissions from transistor switching at a minimum.

Insulating properties between a metallic member supporting a power semiconductor module and an input/output terminal of the power semiconductor module are secured. In a power conversion device in which a bus bar of a connecting member is connected to an input/output terminal and the like of a semiconductor module protruding through an opening of a metallic member, the connecting member includes extended portions which extend in a space between the bus bar and the opening of the metallic member.

A power supply unit for use with thermostats or other like devices. The power supply unit may keep electromagnetic interference emissions and harmonics at a minimum. A unit may have enough power for triggering a switch at about a cross over point of a waveform of input power to the unit. Power for triggering may come from a storage source. Power for the storage source may be provided with power stealing which require switching transistors which can generate emissions. In-line thermostats using MOSFETS power steal may do the power steal during an ON state (triac, relay or silicon controlled rectifier activated). Gate signals to the transistors may be especially shaped to keep emissions from transistor switching at a minimum. All that may be needed, during an OFF state as a bypass, is a high voltage controllable switch. The need may be achieved using high voltage MOSFETS.