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:
Oct. 06, 1992
Filed:
Mar. 11, 1991
Genji Takahashi, Hitachi, JP;
Kazuyuki Seino, Hitachi, JP;
Sadamu Saito, Hitachi, JP;
Tadashi Sato, Mito, JP;
Etsunori Mori, Hitachi, JP;
Kiyoshi Kurosawa, Tokyo, JP;
Yoshinori Shirai, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
The Tokyo Electric Power Co., Inc., Tokyo, JP;
Abstract
An optical d.c. voltage transformer having an electrooptic medium to which a d.c. electrical field or voltage to be measured is to be applied. The electrooptic medium affects the polarized light from the polarizer by an electrooptical effect to a degree proportional to the strength of the electrical field or voltage. The transformer includes a photodetector for producing an optical signal proportional to the affected light received from the electrooptic medium, a device for converting the optical signal from the photodetector into an electrical signal, a chopper for pulsating the electrical field or voltage to be applied to the electrooptic medium, in terms of time, a detector for demodulating the electrical signal from the converting device in synchronism with the pulsated electrical field or voltage, and an output unit for visually presenting the demodulated electrical signal similar in polarity to the electrical field or voltage to be measured.