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:
Feb. 20, 1990
Filed:
May. 30, 1989
Yoshikado Yamada, Kashihara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A light adjusting apparatus comprising a lamp connected to a commercial a.c. power supply via a triac, and a switching control circuit operable by a direct current obtained by directly rectifying the current of the power supply for controlling the conduction timing of the triac based on the zero-cross timing of the power supply. The conduction timing of the triac is controlled by a signal obtained by producing a pulse-width modulated light adjusting signal from a signal generating circuit by a light-emitting element, causing a photodetector in the control circuit to receive the adjusting signal and subjecting the resulting output of the control circuit to pulse-width demodulation.