Heated window assembly

摘要

A heated window assembly e.g. for a motor vehicle, comprises an array of heating elements (2) through which electrical current may be passed from a source of electrical energy (5). The supply of electrical energy to the heating elements is periodically interrupted e.g. as a result of the application of signals from a square-wave generator circuit (8) to the base of a transistor switch (7) in series with the heating elements (2) so that the power consumption of the elements (2) is reduced. The operation is controlled by a timer (9) which allows full-power consumption for an initial period.