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:
Jul. 13, 1982
Filed:
Jun. 30, 1980
Ciro Guajardo, Harbor City, CA (US);
Teledyne Industries, Inc., Los Angeles, CA (US);
Abstract
An improved zero voltage switching AC relay circuit is disclosed which includes two photo sensitive silicon controlled rectifiers (photo-SCRs) connected in inverse parallel as the active switching elements. The photo-SCRs are triggered into conduction by a light source including two light emitting diodes. Zero voltage switching circuitry is also provided which prevents the photo-SCRs from being triggered into conduction by the light source except when the value of the AC voltage being controlled is within a predetermined limit of zero volts. This is accomplished by using the collector-emitter circuit of a transistor to shunt the gate-cathode circuit of each photo-SCR. A transistor is provided for each photo-SCR, and the bases of the transistor are connected to each other by a single current limiting resistor.