A method for manufacturing a spark plug. The method includes: furnishing an insulator; introducing into the insulator a material mixture that is configured to constitute a resistor paste, the material mixture containing ZrO.sub.2 and SiO.sub.2; heating the insulator and the material mixture present therein to a temperature T of at least 870° C., so that ZrO.sub.2 and SiO.sub.2 in the material mixture react at least partly to ZrSiO.sub.4.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.

In some embodiments, a gas discharge tube (GDT) can include first and second electrodes each including an edge and an inward facing surface, such that the inward facing surfaces of the first and second electrodes face each other. The GDT can further include a sealing portion implemented to join and seal the edge portions of the inward facing surfaces of the first and second electrodes to define a sealed chamber between the inward facing surfaces of the first and second electrodes. The GDT can further include an electrically insulating portion implemented to provide a surface in the sealed chamber and to cover a portion of the inward facing surface of each of at least one of the first and second electrodes such that a leakage path within the sealed chamber includes the surface of the electrically insulating portion.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.

An arc fault detection circuit interruption (AFCI) device includes a high frequency arc noise sensor and an arc fault detection circuit for sensing a high frequency arc noise. The high frequency arc noise sensor is disposed across a hot conductor and a neutral conductor and includes a surge protection device and a surge protection circuit such that the surge protection device protects against a first voltage surge in a first range of thousands to hundreds volts and the surge protection circuit protects against a second voltage surge in a second range of hundreds to few volts. The arc fault detection circuit is coupled in series with the high frequency arc noise sensor. The arc fault detection circuit is coupled to a series combination of a trip solenoid or electromagnet and a silicone-controlled rectifier disposed across the hot conductor and the neutral conductor.

An arc fault detection circuit interruption (AFCI) device includes a high frequency arc noise sensor and an arc fault detection circuit for sensing a high frequency arc noise. The high frequency arc noise sensor is disposed across a hot conductor and a neutral conductor and includes a surge protection device and a surge protection circuit such that the surge protection device protects against a first voltage surge in a first range of thousands to hundreds volts and the surge protection circuit protects against a second voltage surge in a second range of hundreds to few volts. The arc fault detection circuit is coupled in series with the high frequency arc noise sensor. The arc fault detection circuit is coupled to a series combination of a trip solenoid or electromagnet and a silicone-controlled rectifier disposed across the hot conductor and the neutral conductor.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.

A chip varistor includes an element body exhibiting varistor characteristics, internal electrodes containing a first electrically conductive material, and an intermediate conductor containing a second electrically conductive material. The intermediate conductor is separated from the internal electrodes in a direction in which the internal electrodes oppose each other, and is disposed between the internal electrodes. At least a part of the intermediate conductor overlaps the internal electrodes in the direction in which the internal electrodes oppose each other. The element body includes a low resistance region in which the second electrically conductive material is diffused. The low resistance region is located between the first and second internal electrodes in the direction in which the first and second internal electrodes oppose each other.