Abstract: A controller adapted to control the temperature of a heating elements with a wide range of positive temperature coefficient of resistance, including very low values, using a sensor in line with the heating element. The controller is able to take account of non-constant mains power supplies and variation in the element resistance over time.

Abstract: A controller adapted to control the temperature of a heating elements with a wide range of positive temperature coefficient of resistance, including very low values, using a sensor in line with the heating element. The controller is able to take account of non-constant mains power supplies and variation in the element resistance over time.

Abstract: An integral water heating assembly is mounted to the tank wall or bottom of a water heater. The integral water heating assembly in accordance with the invention is able to detect conditions such as overheating of the heating element or boil dry conditions and accordingly switch off power to the heating element. This sensing and switching of the electrical power to the water heating element is accomplished without any sensing element external to the water heating assembly housing. The water heating assembly includes a sheathed heating element having ends which pass through apertures in the housing. The heating element preferably has a number of U-shaped bends and an intermediate section which contacts the housing at a point. The electrodes of the heating element are connected to a source of electrical energy through a control unit. The control unit includes a switching element for turning the power on and off, the switching element being controlled by a silicon chip.