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. 11, 2003
Filed:
Mar. 05, 2002
Daniel Liu, Taipei Hsien, TW;
Other;
Abstract
A safety control circuit for an electric water heater includes a voltage detection circuit, a current detection circuit, a load-resistance calculation unit, and a central processing unit. The load-resistance calculation unit calculates load-resistance reference value and dynamic load-resistance values based on voltage value and current value detected by the voltage detection circuit and the current detection circuit, respectively. The central processing unit determines whether there is water supplied to the electric water heater based on the load-resistance reference value and the dynamic load-resistance values sent to the central processing unit by the load-resistance calculation unit. When a difference between the two values is larger than a predefined value, the central processing unit drives a switch to turn off and thereby cut off power supply to the water heater.