To obtain an impact wave by generation of arc discharge between a high-voltage-side electrode 31 connected to a high-voltage-side terminal of a pulse power generating device and a low-voltage-side electrode 32 grounded or connected to a low-voltage-side terminal of the power source. One of the high-voltage-side electrode 31 or the low-voltage-side electrode 32 is an annular electrode formed in an annular shape, the other electrode is a core electrode arranged inside the annular electrode, and arc discharge is generated between an inner peripheral portion of the annular electrode and an outer peripheral portion of the core electrode.

An arrester is disclosed. In an embodiment, the arrester includes a first electrode, a second electrode, a switching contact, a first discharge space between the first and second electrodes and a short-circuiting mechanism suitable for short-circuiting the first and second electrodes and for switching a state of the arrester, wherein, in a first state, at least one electrode of the first and second electrodes is not electrically conductively connected to the switching contact and, in a second state, the at least one electrode is electrically conductively connected to the switching contact.

An arrester is disclosed. In an embodiment, the arrester includes a first electrode, a second electrode, a switching contact, a first discharge space between the first and second electrodes and a short-circuiting mechanism suitable for short-circuiting the first and second electrodes and for switching a state of the arrester, wherein, in a first state, at least one electrode of the first and second electrodes is not electrically conductively connected to the switching contact and, in a second state, the at least one electrode is electrically conductively connected to the switching contact.

A spark plug includes a ground electrode, an insulator, and a center electrode. In a case where a first position of a surface of the ground electrode exposed to a side of an inner wall surface of a cylinder head is a most downstream position in an air flow direction between the center electrode and the ground electrode, and a second position of the inner wall surface of the cylinder head is a position closest to the center electrode on a downstream side of the center electrode in an air flow direction, the spark plug is installed at a position where the first position and the second position are on a same air flow line, or at a position where the first position is recessed to a side where the first position recedes from the inner wall surface than the second position.

A spark plug includes a ground electrode, an insulator, and a center electrode. In a case where a first position of a surface of the ground electrode exposed to a side of an inner wall surface of a cylinder head is a most downstream position in an air flow direction between the center electrode and the ground electrode, and a second position of the inner wall surface of the cylinder head is a position closest to the center electrode on a downstream side of the center electrode in an air flow direction, the spark plug is installed at a position where the first position and the second position are on a same air flow line, or at a position where the first position is recessed to a side where the first position recedes from the inner wall surface than the second position.

An electronic device comprises: a first plate configured to face one surface of the electronic device; a second plate configured to face in a direction opposite to the first plate; a side bezel structure connected to the first plate and the second plate and configured to surround the side of the electronic device; and a printed circuit board mounted in the electronic device and configured to be connected to the side bezel structure, wherein the printed circuit board comprises: a ground area; a first conductive pad, disposed in one area of the printed circuit board, and configured to couple the side bezel structure and the printed circuit board; and a second conductive pad electrically connected to the ground area and disposed between the first conductive pad and the ground area, wherein the first conductive pad and the second conductive pad may be disposed at an interval through which a current, having a voltage equal to or greater than a threshold voltage between the first conductive pad and a second electrode, may flow.

In one embodiment, a device for generating broad spectrum ultraviolet radiation is provided. The device includes an adjustable spark gap of metallic solids, the spark gap including: a first electrode coupled to a first heatsink, and a second electrode coupled to a second heatsink, the second electrode spaced apart and opposite from the first electrode. The device includes a variable capacitor configured to discharge a voltage through the spark gap to generate broad spectrum ultraviolet radiation. The device includes a voltage source. The device includes a controller configured to control the variable capacitor. The first electrode is formed from a first metallic solid and the second electrode is formed from a second metallic solid, and the ultraviolet radiation generated is in the 140 nm to 400 nm range.

In one embodiment, a device for generating broad spectrum ultraviolet radiation is provided. The device includes an adjustable spark gap of metallic solids, the spark gap including: a first electrode coupled to a first heatsink, and a second electrode coupled to a second heatsink, the second electrode spaced apart and opposite from the first electrode. The device includes a variable capacitor configured to discharge a voltage through the spark gap to generate broad spectrum ultraviolet radiation. The device includes a voltage source. The device includes a controller configured to control the variable capacitor. The first electrode is formed from a first metallic solid and the second electrode is formed from a second metallic solid, and the ultraviolet radiation generated is in the 140 nm to 400 nm range.

An electrode device includes a discharge electrode and a counter electrode, and discharges when a voltage is applied across the discharge electrode and the counter electrode. The discharge electrode is a columnar electrode having a discharge portion on its front end. The counter electrode faces the discharge portion. The counter electrode has a peripheral electrode portion and a projecting electrode portion. The peripheral electrode portion is disposed to surround an axis of the discharge electrode. The projecting electrode portion projects from a part of the peripheral electrode portion toward the axis of the discharge electrode. A distance from the peripheral electrode portion to the discharge portion is shorter than a distance from the projecting electrode portion to the discharge portion.

In one embodiment, a device for generating broad spectrum ultraviolet radiation is provided. The device includes an adjustable spark gap of metallic solids, the spark gap including: a first electrode coupled to a first heatsink, and a second electrode coupled to a second heatsink, the second electrode spaced apart and opposite from the first electrode. The device includes a variable capacitor configured to discharge a voltage through the spark gap to generate broad spectrum ultraviolet radiation. The device includes a voltage source. The device includes a controller configured to control the variable capacitor. The first electrode is formed from a first metallic solid and the second electrode is formed from a second metallic solid, and the ultraviolet radiation generated is in the 140 nm to 400 nm range.