The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 27, 1979
Filed:
Sep. 06, 1977
Hitachi, Ltd., , JP;
Abstract
A solid state relay or controlled switch for connecting an AC power source to a load includes a solid state switching circuit in which a semiconductor controlled rectifier element, such as a photothyristor, thyristor or light-AC controlled element, is ignited by an external control signal, thereby to feed a load with an alternating current. A zero voltage switching circuit which executes switching when the instantaneous value of the amplitude of the supply voltage of the AC load current is zero or a value close thereto is connected to the rectifier element. As an improvement, a series circuit consisting of a resistor and a capacitor are connected between the base and emitter of a transistor in the zero voltage switching circuit. Thus, a zero voltage switching solid state relay whose withstand voltage build-up rate is enhanced and whose switching is endowed with a hysteresis characteristic is provided.