Abstract: An electrical quantity sensor includes, an oscillation circuit for producing a clock signal of predetermined frequency, a light-emitting element which blinks at a predetermined frequency in accordance with the clock signal output from the oscillation circuit, a switching element which is optically coupled to the light-emitting element and is brought into conduction when the light-emitting element illuminates, a transformer whose primary winding is connected, by way of the switching element, to input terminals which receive a d.c. electrical signal and a synchronization detecting circuit which synchronously detects an a.c. electric signal developing in a secondary winding of the transformer while the clock signal is taken as a reference, thereby producing a d.c. voltage signal corresponding to the amplitude of the d.c. electric signal.

Abstract: A contact apparatus is provided having a permanent magnet disposed in a region where a fixing contact point is mounted to a fixing contact and a movable contact to which a movable contact point is mounted. An arc generated between both the contact points is moved in a lateral direction by the magnetic force of the permanent magnet and stretched. An arc-extinguishing member which is heated by the arc for generating arc-extinguishing gas is provided such as to surround the fixing contact point and the movable contact point.

Abstract: An electrical quantity sensor includes, an oscillation circuit for producing a clock signal of predetermined frequency, a light-emitting element which blinks at a predetermined frequency in accordance with the clock signal output from the oscillation circuit, a switching element which is optically coupled to the light-emitting element and is brought into conduction when the light-emitting element illuminates, a transformer whose primary winding is connected, by way of the switching element, to input terminals which receive a d.c. electrical signal and a synchronization detecting circuit which synchronously detects an a.c. electric signal developing in a secondary winding of the transformer while the clock signal is taken as a reference, thereby producing a d.c. voltage signal corresponding to the amplitude of the d.c. electric signal.

Abstract: A sealed contact unit that attains stabilized contact switching operation and effective dimensional minimization with an arrangement wherein a switching contact section including opposing movable and stationary contacting members is housed within a sealed container together with an electrically insulating gas, a movable shaft interlocked to the movable contacting member is hermetically passed through a wall of the container to be axially shiftable with an end projected externally while the movable contacting member biased away from the stationary contacting member by a resetting spring is mounted through a contact-pressure spring to the other end of the movable shaft inside the container, the contact-pressure spring being provided to coaxially enclose the movable shaft and biasing the movable contacting member against the biasing force of the resetting spring for attaining a contact-pressure when the movable contact member shifts to engage the stationary contact member fixed inside the container, a driving se

Abstract: A sealed contact device is formed by disposing a fixed electrode having a fixed contact in an air-tight space defined in a hermetical container in which an electrically insulating gas is sealed at a high pressure, a movable contact of a movable electrode is provided for contact opening and closing with the fixed contact, and means is provided with respect to the movable electrode for allowing it positively movable in the air-tight manner, whereby an optimum contact opening speed of the movable contact and at the same time a proper contact pressure are both obtainable.