An analog amplification vacuum tube of the present invention suppresses influences of filament vibration on amplification characteristics. The analog amplification vacuum tube of the present invention is provided with a filament, an anode, a grid and a vibration-proof part. The filament is tensioned linearly and emits thermal electrons. The anode is disposed parallel to the filament. The grid is disposed between the filament and the anode so as to face the anode. The vibration-proof part includes a thin film usable in a vacuum environment and the thin film comes into contact with part of the filament.

An analog amplification vacuum tube of the present invention suppresses influences of filament vibration on amplification characteristics. The analog amplification vacuum tube of the present invention is provided with a filament, an anode, a grid and a vibration-proof part. The filament is tensioned linearly and emits thermal electrons. The anode is disposed parallel to the filament. The grid is disposed between the filament and the anode so as to face the anode. The vibration-proof part includes a thin film usable in a vacuum environment and the thin film comes into contact with part of the filament.

An analog amplification vacuum tube of the present invention suppresses influences of filament vibration on amplification characteristics. The analog amplification vacuum tube of the present invention is provided with a filament, an anode, a grid and a vibration-proof part. The filament is tensioned linearly and emits thermalelectrons. The anode is disposed parallel to the filament. The grid is disposed between the filament and the anode so as to face the anode. The vibration-proof part includes a thin film usable in a vacuum environment and the thin film comes into contact with part of the filament.

An analog amplification vacuum tube of the present invention suppresses influences of filament vibration on amplification characteristics. The analog amplification vacuum tube of the present invention is provided with a filament, an anode, a grid and a vibration-proof part. The filament is tensioned linearly and emits thermalelectrons. The anode is disposed parallel to the filament. The grid is disposed between the filament and the anode so as to face the anode. The vibration-proof part includes a thin film usable in a vacuum environment and the thin film comes into contact with part of the filament.

An ion generator including a vacuum chamber; an anode in the chamber, and two movable cathodes in the chamber whereby the distance of the cathodes relative to the anode can be varied. A servo actuated motor can be operably connected to each movable cathode to move the cathodes in the chamber and modify the plasma generated.

A spark plug has a central electrode and a plurality of peripheral electrodes. The central electrode has a proximal portion and a distal portion. The distal portion of the central electrode has a circular cross-section with a longitudinal axis and terminates in a distal end. Each peripheral electrode has a lower portion and an upper portion. Each upper portion has a distal-most point. Each distal-most point is disposed in a central plane within which the longitudinal axis of the distal portion of the central electrode is wholly disposed. The cross-section of each upper portion taken along its central plane defines a convex outer side and a non-convex inner side. Each convex outer side has a curved surface which is tangent to a plurality of tangent planes, all of which intersect the longitudinal axis of the distal portion of the central electrode at points at or above the distal end of the distal point of the central electrode.