A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

A corona comprises a central electrode surrounded by an insulator, which is surrounded by a conductive component. The conductive component includes a shell and an intermediate part both formed of an electrically conductive material. The intermediate part is a layer of metal which brazes the insulator to the shell. An outer surface of the insulator presents a lower ledge, and the layer of metal can be applied to the insulator above the lower ledge prior to or after inserting the insulator into the shell. The conductive inner diameter is less than an insulator outer diameter directly below the lower ledge such the insulator thickness increases toward the electrode firing end. The insulator outer diameter is also typically less than the shell inner diameter so that the corona igniter can be forward-assembled.

A discharge device according to the present disclosure includes a discharge electrode and a voltage applicator that applies a voltage to the discharge electrode and thus causes discharge that is further developed from corona discharge at the discharge electrode. The discharge is discharge in which a discharge path is intermittently formed by dielectric breakdown so as to stretch from the discharge electrode to a surrounding. This discharge can be called leader discharge. This makes it possible to increase an amount of generated active component while keeping an increase of ozone small.

A discharge device according to the present disclosure includes a discharge electrode and a voltage applicator that applies a voltage to the discharge electrode and thus causes discharge that is further developed from corona discharge at the discharge electrode. The discharge is discharge in which a discharge path is intermittently formed by dielectric breakdown so as to stretch from the discharge electrode to a surrounding. This discharge can be called leader discharge. This makes it possible to increase an amount of generated active component while keeping an increase of ozone small.

The present disclosure provides an over-voltage protection device. The over-voltage protection device includes a substrate, a stack structure disposed over the substrate. The stack structure includes a first insulation structure, a second insulation structure, and a conductive layer. The conductive layer is disposed on the first insulation structure, and the second insulation structure is disposed on the conductive layer. The second insulation structure has an insulation air gap, which has an upper width greater than a lower width.

A corona igniter (20) comprises a central electrode (22) surrounded by an insulator (24), which is surrounded by a metal shell (26). A ceramic combustion seal (30) is disposed along the gap (32) between a shell lower end shell (52) and the insulator nose region (48) to provide a hermetic seal therebetween. The ceramic combustion seal (30) is typically a bushing, cylinder, or ring formed of sintered alumina. A glass material or glass/ceramic mixture (60) typically adheres the ceramic combustion seal (30) to the shell (26) and the insulator (24). Alternatively, the ceramic combustion seal (30) is brazed to the shell (26), and the glass material or glass/ceramic mixture (60) adheres the ceramic combustion seal (30) to the insulator (24).

A corona igniter (20) comprises a central electrode (22) surrounded by an insulator (24), which is surrounded by a metal shell (26). A ceramic combustion seal (30) is disposed along the gap (32) between a shell lower end shell (52) and the insulator nose region (48) to provide a hermetic seal therebetween. The ceramic combustion seal (30) is typically a bushing, cylinder, or ring formed of sintered alumina. A glass material or glass/ceramic mixture (60) typically adheres the ceramic combustion seal (30) to the shell (26) and the insulator (24). Alternatively, the ceramic combustion seal (30) is brazed to the shell (26), and the glass material or glass/ceramic mixture (60) adheres the ceramic combustion seal (30) to the insulator (24).

An ESD protection device includes a bare unitary body, and a first discharge electrode and a second discharge electrode that are disposed inside the bare unitary body. The first discharge electrode and the second discharge electrode are opposed to each other with a gap interposed therebetween. The bare unitary body includes a cavity in which the gap between the first discharge electrode and the second discharge electrode is located, and to which the first discharge electrode and the second discharge electrode are exposed. A first space of the cavity on a side closer to the first discharge electrode is smaller than a second space of the cavity on a side closer to the second discharge electrode.

An ESD protection device includes a bare unitary body, and a first discharge electrode and a second discharge electrode that are disposed inside the bare unitary body. The first discharge electrode and the second discharge electrode are opposed to each other with a gap interposed therebetween. The bare unitary body includes a cavity in which the gap between the first discharge electrode and the second discharge electrode is located, and to which the first discharge electrode and the second discharge electrode are exposed. A first space of the cavity on a side closer to the first discharge electrode is smaller than a second space of the cavity on a side closer to the second discharge electrode.

A triggerable spark gap, a switching circuit and a method for manufacturing a triggerable spark gap are disclosed. In an embodiment, a triggerable spark gap includes a trigger electrode, an adjacent electrode at the trigger electrode, a counter electrode and a gap between the counter electrode and the adjacent electrode, wherein a distance between the trigger electrode and the adjacent electrode is less than a distance between the trigger electrode and the counter electrode, wherein the distance between the trigger electrode and the counter electrode is less than a distance between the adjacent electrode and the counter electrode, wherein the counter electrode and/or the adjacent electrode includes a first phase including a first material and a second phase including a second material, and wherein the second material has a lower electron work function than the first material.