A switchable wire includes filaments, each of which includes a heat-activated material layer that may be indirectly heated to change its state between different states having different electrical conductivity. In an example embodiment the indirect heating may be electrically resistance heating by passing electrical current through an electrically-resistive core of the filament. The heat passing through an electrically-insulative coating around the core, and into a heat-activated material layer around the electrically-insulative coating. The heat-activated material may be a chalcogenide material that is shiftable between a crystalline electrically-conducting state and an amorphous electrically-insulating state. The state of the material may be controlled by controlling the heating profile through controlling heating in the core. Many such filaments may be twisted together to form a switchable wire. Such wires may be used in any of a variety of devices where switchable electrical conductivity is desired.

A switchable wire includes filaments, each of which includes a heat-activated material layer that may be indirectly heated to change its state between different states having different electrical conductivity. In an example embodiment the indirect heating may be electrically resistance heating by passing electrical current through an electrically-resistive core of the filament. The heat passing through an electrically-insulative coating around the core, and into a heat-activated material layer around the electrically-insulative coating. The heat-activated material may be a chalcogenide material that is shiftable between a crystalline electrically-conducting state and an amorphous electrically-insulating state. The state of the material may be controlled by controlling the heating profile through controlling heating in the core. Many such filaments may be twisted together to form a switchable wire. Such wires may be used in any of a variety of devices where switchable electrical conductivity is desired.

This application discloses a photovoltaic direct-current breaking apparatus, including a positive connection terminal and a negative connection terminal for connecting a photovoltaic string and a photovoltaic energy converter, a first diode, a first switch, a convector circuit, and an energy absorption circuit, where the first switch, the convector circuit, and the energy absorption circuit are connected in parallel. The convector circuit can effectively avoid arc discharge and ablation generated when the first switch cuts off a direct-current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, helping reduce required specifications of a semiconductor device in the convector circuit. The energy absorption circuit can also effectively reduce required specifications of the semiconductor device and a varistor.

This application discloses a photovoltaic direct-current breaking apparatus, including a positive connection terminal and a negative connection terminal for connecting a photovoltaic string and a photovoltaic energy converter, a first diode, a first switch, a convector circuit, and an energy absorption circuit, where the first switch, the convector circuit, and the energy absorption circuit are connected in parallel. The convector circuit can effectively avoid arc discharge and ablation generated when the first switch cuts off a direct-current circuit between the photovoltaic string and the photovoltaic energy converter. The first diode can effectively bypass energy stored by an energy storage device in the photovoltaic energy converter, helping reduce required specifications of a semiconductor device in the convector circuit. The energy absorption circuit can also effectively reduce required specifications of the semiconductor device and a varistor.

A wall-mountable load control device may include an illuminated rotary knob for providing a nightlight feature. The load control device may be configured to control an intensity of a lighting load. The load control device may include a yoke adapted to be mounted to an electrical wall box, an enclosure attached to the yoke, a faceplate attached to the yoke and having an opening, a mounting member attached to the yoke, and/or a potentiometer located within the enclosure and having a shaft extending through an opening in the yoke and the opening of the faceplate. The load control device may include a collar attached to the boss of the mounting member and surrounding the shaft of the potentiometer. The mounting member may be configured to conduct light from at least one light source housed within the enclosure to illuminate the faceplate.

A wall-mountable load control device may include an illuminated rotary knob for providing a nightlight feature. The load control device may be configured to control an intensity of a lighting load. The load control device may include a yoke adapted to be mounted to an electrical wall box, an enclosure attached to the yoke, a faceplate attached to the yoke and having an opening, a mounting member attached to the yoke, and/or a potentiometer located within the enclosure and having a shaft extending through an opening in the yoke and the opening of the faceplate. The load control device may include a collar attached to the boss of the mounting member and surrounding the shaft of the potentiometer. The mounting member may be configured to conduct light from at least one light source housed within the enclosure to illuminate the faceplate.

A resistor assembly can be used in a tap changer. The resistor assembly may include: a resistor element, which is held by at least two resistor holders; a base plate with at least one opening and on which the at least two resistor holders holding the resistor element are arranged; a plurality of guides, respectively formed in each of the resistor holders and being configured to position a first end and a second end of the resistor element with respect to a longitudinal direction between the two resistor holders; and contact points of the resistor element, the contact points being electrically contacted by contacts of the tap changer in a condition where the resistor element is inserted into the resistor holder.

The invention relates to a switch including a switch housing, a contact system and a base disposed in the switch housing, a resistive element for diagnosing a state of a switch, and at least two terminals leading from the base. The resistive element has a specific resistance value. The resistive element is a conductive material formed on the base, the terminals being electrically connected by the conductive material.

A variable resistor includes: a main body and a rotating part vertically separated away from each other, among which the main body includes: a substrate having a first main surface, a second main surface and a through hole vertically penetrating the first main surface and the second main surface; a first conductive portion and a second conductive portion provided on the first main surface; a resistor body connected thereto; an electrode positioned closer to the through hole than the resistor body; and a third conductive portion (i) provided on each of the second main surface and a partition wall surface for partitioning the through hole and (ii) connected to the electrode, and the rotating part includes: an opposing part rotatable in a circumferential direction; and a slider configured to conductively slide as the rotating part rotates.

A method for calibrating a resistance value comprises the steps of measuring a value of a reference capacitor, and adjusting a variable resistor based on the measured value of the reference capacitor. The method may more specifically comprise the steps of directing a constant current through the reference capacitor during a reference time interval; after the reference time interval, directing the constant current through the variable resistor; and varying the variable resistor value progressively by varying a control signal until a voltage of the variable resistor reaches a voltage of the reference capacitor.