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. 01, 1994
Filed:
Feb. 24, 1993
Warren G Lohoff, San Antonio, TX (US);
Pass & Seymour Legrand, San Antonio, TX (US);
Abstract
A low voltage dimmer is shown with the dimming function being on a primary side of a low voltage transformer. Live voltage feeds through a triac to the primary side of the transformer with the gate for the triac being controlled by a microprocessor. To prevent burnout of the transformer if the secondary load side is open, zero crossing of the incoming signal is determined by the microprocessor. If the time constant between the zero crossing of the live voltage and the charging of a capacitor with resistance being provided by the primary side of the transformer exceeds w predetermined time period, the microprocessor will be inhibited from generating a pulse to fire the triac. When the primary side of the transformer has been opened, the load on the secondary side can be re-established, i.e. light bulb replaced. Power for the microprocessor is from the charging of a capacitor used to provide the triggering signal to the microprocessor. Also the microprocessor may be triggered from remote locations.