An object is to provide a laminated varistor excellent in clamping voltage ratio. Laminated varistor includes at least a pair of internal electrodes provided in varistor layer containing ZnO as a main component. Internal electrode contains Ag as a main component and is made of a metal containing at least one type selected from Pt and Au. The total weight of Pt and Au with respect to the weight of the metal constituting internal electrode is set between 2% and 30% (inclusive). With such a configuration, diffusion of Ag into varistor layer can be prevented, and a laminated varistor excellent in clamping voltage ratio can be obtained.

An object is to provide a laminated varistor excellent in clamping voltage ratio. Laminated varistor includes at least a pair of internal electrodes provided in varistor layer containing ZnO as a main component. Internal electrode contains Ag as a main component and is made of a metal containing at least one type selected from Pt and Au. The total weight of Pt and Au with respect to the weight of the metal constituting internal electrode is set between 2% and 30% (inclusive). With such a configuration, diffusion of Ag into varistor layer can be prevented, and a laminated varistor excellent in clamping voltage ratio can be obtained.

A varistor includes a sintered body, an internal electrode, an insulating layer, and an external electrode. The internal electrode is disposed in an interior of the sintered body. The insulating layer covers at least part of the sintered body and includes Zn.sub.2SiO.sub.4. The external electrode is electrically connected to the internal electrode, covers part of the sintered body and part of the insulating layer, and is in contact with the part of the insulating layer. The insulating layer has a region being in contact with the external electrode, the region having a greater average thickness than a region of the insulating layer which is out of contact with the external electrode.

A varistor includes a sintered body, an internal electrode, an insulating layer, and an external electrode. The internal electrode is disposed in an interior of the sintered body. The insulating layer covers at least part of the sintered body and includes Zn.sub.2SiO.sub.4. The external electrode is electrically connected to the internal electrode, covers part of the sintered body and part of the insulating layer, and is in contact with the part of the insulating layer. The insulating layer has a region being in contact with the external electrode, the region having a greater average thickness than a region of the insulating layer which is out of contact with the external electrode.

In an embodiment a method for manufacturing a multilayer varistor includes providing a first ceramic powder for producing a first ceramic material and at least one second ceramic powder for producing a second ceramic material, wherein the ceramic powders differ from each other in concentration of monovalent elements X.sup.+ by 50 ppmc(X.sup.+)5000 ppm, wherein X.sup.+=(Li.sup.+, Na.sup.+, K.sup.+ or Ag.sup.+), and wherein c denotes a maximum concentration difference occurring between an active region and a near-surface region of the multilayer varistor, slicking of the ceramic powders and forming of green films, partially printing of a part of the green films with a metal paste to form inner electrodes, stacking printed and unprinted green films, laminating, decarbonizing and sintering the green films and applying outer electrodes.

In an embodiment a method for manufacturing a multilayer varistor includes providing a first ceramic powder for producing a first ceramic material and at least one second ceramic powder for producing a second ceramic material, wherein the ceramic powders differ from each other in concentration of monovalent elements X.sup.+ by 50 ppmc(X.sup.+)5000 ppm, wherein X.sup.+=(Li.sup.+, Na.sup.+, K.sup.+ or Ag.sup.+), and wherein c denotes a maximum concentration difference occurring between an active region and a near-surface region of the multilayer varistor, slicking of the ceramic powders and forming of green films, partially printing of a part of the green films with a metal paste to form inner electrodes, stacking printed and unprinted green films, laminating, decarbonizing and sintering the green films and applying outer electrodes.

A metal oxide varistor (MOV) includes an MOV body, a first electrode, a second electrode, and a thermal cut-off insulation shell. The MOV body is a crystalline microstructure with zinc oxide mixed with one or more other metal oxides. The first electrode is adjacent one side of the MOV body and is connected to a first radial lead. The second electrode is adjacent a second side of the MOV body and is connected to a second radial lead having a curved portion. The thermal cut-off insulation shell is adjacent the second electrode and has a protrusion, with the curved portion of the second radial lead being adjacent the protrusion.

Integrated device having GDT and MOV functionalities. In some embodiments, an electrical device can include a first layer and a second layer joined with an interface, with each having an outer surface and an inner surface, such that the inner surfaces of the first and second layers define a sealed chamber therebetween. The electrical device can further include an outer electrode implemented on the outer surface of each of the first and second layers, and an inner electrode implemented on the inner surface of each of the first and second layers. The first layer can include a metal oxide material such that the first outer electrode, the first layer, and the first inner electrode provide a metal oxide varistor (MOV) functionality, and the first inner electrode, the second inner electrode, and the sealed chamber provide a gas discharge tube (GDT) functionality.

Integrated device having GDT and MOV functionalities. In some embodiments, an electrical device can include a first layer and a second layer joined with an interface, with each having an outer surface and an inner surface, such that the inner surfaces of the first and second layers define a sealed chamber therebetween. The electrical device can further include an outer electrode implemented on the outer surface of each of the first and second layers, and an inner electrode implemented on the inner surface of each of the first and second layers. The first layer can include a metal oxide material such that the first outer electrode, the first layer, and the first inner electrode provide a metal oxide varistor (MOV) functionality, and the first inner electrode, the second inner electrode, and the sealed chamber provide a gas discharge tube (GDT) functionality.

The present disclosure relates to a semiconductor circuit breaker and, more specifically, to a semiconductor circuit breaker in which a protection circuit is modularized and thus maintenance and repair can be easily done. A semiconductor circuit breaker according to an embodiment of the present disclosure comprises: a main circuit unit connected between a power source and a load and having a semiconductor switch; an outer box equipped with the main circuit unit and having a module accommodation unit outside thereof; and a protection module detachably accommodated in the module accommodation unit.