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:
Nov. 07, 1978
Filed:
Jan. 13, 1978
Robert Colman, New York, NY (US);
Metaframe Corporation, Elmwood Park, NJ (US);
Abstract
An aquarium water heater having a heater element energized by first and second silicon-controlled rectifiers connected in parallel in opposing conductive relation, one rectifier providing energy to the heater element on one-half cycle of alternating current while simultaneouly charging a capacitor which is connected to the gate electrode of the second rectifier for rendering the second rectifier conductive on the other half cycle of alternating current to supply energy to the heater element. Circuit means are connected to the gate electrode of the first rectifier, the circuit means including a thermistor for sensing the water temperature and rendering the first rectifier non-conductive when the water temperature equals a set point determined by a rheostat in the circuit means.