Surge protective devices

A printed circuit board assembly comprising:

• a printed circuit board (PCB);
• a surge protective device (SPD) subassembly mounted on the PCB, the SPD subassembly including:
• a first electrode comprised of a housing electrode defining a cavity and a housing electrode opening communicating with the cavity;
• a second electrode;
• and
• a varistor electrically connected between the first and second electrodes and contained in the cavity;
• wherein the first electrode and the PCB each form parts of a housing assembly defining a chamber containing the varistor and the PCB closes the housing electrode opening to enclose the chamber.

A power supply circuit comprising:

• a surge protective device (SPD) module comprising:
• a printed circuit board (PCB);
• a first electrode comprised of a housing electrode defining a cavity and a housing electrode opening communicating with the cavity;
• a second electrode;
• and
• a varistor electrically connected between the first and second electrodes and contained in the cavity;
• wherein:
• the SPD module forms a housing assembly defining a chamber containing the varistor;
• and
• the PCB forms a portion of the housing assembly and closes the housing electrode opening to enclose the chamber;
• a first electrical line at a first electrical potential connected to the first electrode;
• and
• a second electrical line at a second electrical potential connected to the second electrode.