Abstract: A pressure sensor includes a detection unit 1 having capacities C1 and C2 varied by a predetermined external action, a reference detection 2 unvaried by the predetermined external action, a first oscillator 31 and 32 for generating a detection frequency signal according to the capacities C1 and C2 of the detection unit 1, a second oscillator 33 for producing a reference frequency signal according to the capacity of the reference unit 2, and measuring circuits 34, 35, 36 and 37 for measuring the number of the periods of the detection frequency signal within a predetermined period of the reference frequency signal to produce a measured signal. The sensor can minimize a detection error, and directly convert the change of capacity into a pulse signal (digital signal) without convertion into an analog, so that the circuit construction be simplified and realized at a reduced cost.

Abstract: A switch in which an armature swingably coupled to a stationary terminal is operated by a depression of a push button to trip between the contacts. A movable spring is laid between the stationary terminal and the armature to assist the trip of the armature and the stationary terminal is welded to the armature. The switch can be manufactured relatively readily without increase in the number of components, and is high in the reliability in electrical connection of the stationary terminal and the armature.