The electric kettle is a very simple device. It basically accommodates a coiled heating element which is fixed into the base of the kettle. Because this coil is so long it dissipates a huge amount of heat, which in turn boils the water rapidly.
Many kettles contain a thermostat which controls the supply of current passing through the element. The main use of this is to guarantee that when the water is boiling, the current automatically disconnects. This technique prevents the kettle from boiling dry if it has been left unattended.
