A protection device is provided for electric appliances suitable for selectively connecting an electric appliance to a power supply line. The protection device includes a metal plate member, a composite metal blade, an insulating block for supporting the metal plate member and the composite metal blade, and a compensating resistor made en bloc with the metal plate member.

A protection device is provided for electric appliances suitable for selectively connecting an electric appliance to a power supply line. The protection device includes a metal plate member, a composite metal blade, an insulating block for supporting the metal plate member and the composite metal blade, and a compensating resistor made en bloc with the metal plate member.

A phase change material switch device is provided. The phase change material switch device includes a phase change material, a first electrode electrically coupled to the phase change material, and at least one heater thermally coupled to the phase change material. An equalization device is configured to provide an impedance coupling between the first electrode and the phase change material. The impedance coupling varies over the phase change material.

A phase change material switch device is provided. The phase change material switch device includes a phase change material, a first electrode electrically coupled to the phase change material, and at least one heater thermally coupled to the phase change material. An equalization device is configured to provide an impedance coupling between the first electrode and the phase change material. The impedance coupling varies over the phase change material.