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:
Dec. 15, 1987
Filed:
Oct. 29, 1986
Edgar M Smith, Lancaster County, PA (US);
RCA Corporation, Princeton, NJ (US);
Abstract
A relay switch in an ac main line has a dc-powered applying for applying amplified control sensor signals to the control circuit of the relay switch. To provide dc power for the amplifier when the relay switch main controlled current conduction path is conductive, a current transformer primary winding is arranged in series with that path, and the voltage appearing across the secondary winding is rectified. To provide dc power for the amplifier when the relay switch main controlled current conduction path is non-conductive, an open-circuit voltage related to that appearing across the open-circuit non-conductive path is rectified. To permit the use of one rectifier for developing dc power for the amplifier it is advantageous to apply the open-circuit voltage to the secondary winding of the current transformer through a dc-blocking capacitor with sufficient ac impedance to restrict ac flow across the open-circuit relay switch path.