BOILING SENSOR

摘要

The invention provides a water-boiling sensor usable in electric kettles, or other water-boiling appliances incorporating an electrically powered heating element, to reliably detect when the water boils. The sensor is wholly electronic and preferably can also be used to detect the water level. It utilises a capacitive detection element comprising electrodes (10, 12), disposed in contact with water in the kettle or other appliance, and connected to an oscillator (16) or other circuit generating electrical signals that are influenced by the capacitance between the electrodes (10, 12), and which exhibit a peculiar and repeatable characteristic response (2, 3) when the water boils. Electrical circuitry (18) is provided to recognise electrical signals having the aforementioned characteristic response and to then develop control signals usable to disconnect the power from the heating element when the water boils. The invention also encompasses an electric kettle, or other water-heating appliance, incorporating such a sensor.