A membrane circuit structure having a plurality of switch regions includes first, second and third membranes and a spacer layer. The second membrane is beneath the first membrane, and a lower surface of the second membrane is provided with a conductive pattern in at least one of the switch regions. The spacer layer is disposed between the first and second membranes. The third membrane is beneath the second membrane, and an upper surface of the third membrane is provided with first and second trigger portions separated from each other in the at least one of the switch regions, and the conductive pattern is able to be in contact with the first and second trigger portions, so that the first and second trigger portions are able to be electrically connected to each other through the conductive pattern.

A high-voltage direct current relay capable of improving insulation capability, including a ceramic cover, two fixed contacts for respectively providing inflow and outflow current and one movable contact spring; a through hole for assembling the fixed contact being provided at a top wall of the ceramic cover; one segment of a body of the fixed contact being in clearance fitted with the through hole of the ceramic cover, a first step surface downward being provided at an outer peripheral wall of one segment of the body of the fixed contact, at a corresponding position, a second step surface upward being provided at an inner peripheral wall of the through hole of the ceramic cover, and the projections of the first step surface and the second step surface on the horizontal plane having an overlapped region.

A high-voltage direct current relay capable of improving insulation capability, including a ceramic cover, two fixed contacts for respectively providing inflow and outflow current and one movable contact spring; a through hole for assembling the fixed contact being provided at a top wall of the ceramic cover; one segment of a body of the fixed contact being in clearance fitted with the through hole of the ceramic cover, a first step surface downward being provided at an outer peripheral wall of one segment of the body of the fixed contact, at a corresponding position, a second step surface upward being provided at an inner peripheral wall of the through hole of the ceramic cover, and the projections of the first step surface and the second step surface on the horizontal plane having an overlapped region.

A high- or medium-voltage circuit breaker, in which a movable contact (1) is moved in sliding in order to separate stationary contacts (11, 12) from its sliding surface (2). In accordance with the invention, the stationary contacts (11, 12) have switching portions (9) that separate from the movable contact more or less simultaneously as a result of a setback (19) in the movable contact (1), thereby causing two simultaneous switching arcs to appear (14, 15), which arcs are extinguished much more quickly than a single arc, before the current is transferred to the conventional arcing contacts (5). This disposition enables the stationary contacts (11, 12) and their environment to be less exposed to damage.

A dome-shaped push switch includes a sheet and a conducting layer disposed at a low surface of the sheet. The sheet has a pressing portion arching upward. The conducting layer is disposed at a lower surface of the sheet. The conductivity of the sheet is greater than that of the sheet. The pressing portion includes at least one through hole penetrating through the pressing portion. The through hole has a side wall, the side wall sequentially has a shear surface and a tear surface from bottom up, and a fillet is provided between the shear surface and a lower surface of the pressing portion.

A dome-shaped push switch includes a sheet and a conducting layer disposed at a low surface of the sheet. The sheet has a pressing portion arching upward. The conducting layer is disposed at a lower surface of the sheet. The conductivity of the sheet is greater than that of the sheet. The pressing portion includes at least one through hole penetrating through the pressing portion. The through hole has a side wall, the side wall sequentially has a shear surface and a tear surface from bottom up, and a fillet is provided between the shear surface and a lower surface of the pressing portion.

A longitudinal switch for an electric contact locking and position changing system was designed to position securely the movable switch elements (7), which are urged by springs (5) and a rack (1) and toothed gear (8) mechanism for moving a vertical shaft (9), acting upon fixed elements (contacts) (16) of an electrically insulating rail surface (15). Positions are changed by turning a control button (39) and the toothed gear (8), causing the vertical shaft (9) to rotate, thus moving the rack (1) and causing the movable elements (7) to slide on the semicircular surface (17) of the fixed elements (16), overcoming the force of the springs (5) and compressing them. Once the gap between the fixed elements (16) is located, the springs (5) push back, keeping the movable elements (7) locked and ensuring the effective electric contact with the electric current passing through these points of contact.

A longitudinal switch for an electric contact locking and position changing system was designed to position securely the movable switch elements (7), which are urged by springs (5) and a rack (1) and toothed gear (8) mechanism for moving a vertical shaft (9), acting upon fixed elements (contacts) (16) of an electrically insulating rail surface (15). Positions are changed by turning a control button (39) and the toothed gear (8), causing the vertical shaft (9) to rotate, thus moving the rack (1) and causing the movable elements (7) to slide on the semicircular surface (17) of the fixed elements (16), overcoming the force of the springs (5) and compressing them. Once the gap between the fixed elements (16) is located, the springs (5) push back, keeping the movable elements (7) locked and ensuring the effective electric contact with the electric current passing through these points of contact.

A contact device includes a moving contactor, a pair of moving contacts arranged in one direction, a pair of fixed terminals, and a pair of fixed contacts. At least one fixed terminal, selected from the pair of fixed terminals, includes a contact holder. The contact holder includes a first fixed extension and a second fixed extension. As for either a current component flowing in the one direction into the fixed contact or a current component flowing in the one direction out of the fixed contact, the current component flowing through the first fixed extension has a larger amount of current than a current component flowing through the second fixed extension.

An electromagnetic relay includes a pair of fixed terminals, a movable contact piece, and a magnet portion. The pair of fixed terminals includes fixed contact. The movable contact piece that includes a movable contact disposed facing the fixed contact and that is movable in a first direction in which the movable contact contacts the fixed contact and in a second direction in which the movable contact separates from fixed contact. The magnet portion generating a magnetic field for extending an arc generated between the fixed contact and the movable contact. At least one of a corner portion in the first direction side of the fixed terminal located in an arc extension direction in which the arc is extended or a corner portion in the second direction side of the movable contact piece located in the arc extension direction has a chamfered shape in a range where the arc passes through.