Patent ID: 7800027

Claim:
A method of calibrating a water temperature for an electric kettle containing a predetermined amount of water, and comprising a temperature sensor, a microprocessor, a control circuit and a heating source defining a heating point for delivering heat energy, wherein said method comprises the steps of: (a) controllably heating said water within said electric kettle, and assigning a predetermined interval of heating time as a heating cycle by said microprocessor so as to divide an entire heating time of said electric kettle into a predetermined number of consecutive heating cycles; (b) detecting an interior temperature of said kettle by said temperature sensor, wherein said interior temperature of said kettle is defined by one of a temperature of said water contained in said water kettle, a temperature of said heating point of said heating source, or said temperature of an interior wall of said electric kettle; (c) when said interior temperature reaches a predetermined a temperature threshold, determining a rate of change of said interior temperature by said microprocessor for each heating cycle; (d) for each two consecutive heating cycles, comparing said rate of change of interior temperature of each heating cycle with said rate of change of interior temperature of said subsequent heating cycle by said microprocessor; and (e) when said rates of change of interior temperature of two consecutive heating cycles are substantially the same, turning off said heating source by said control circuit to stop heating up said water.