Abstract: An electric circuit for capacitive sensor elements of a touch switch can be designed as a switch capacitor circuit and van be provided with a micro controller. The sensor elements are provided in sensor branches with a charging capacitor. In addition, a reference branch is provide. It contains a reference capacity and a reference charging capacitor, which have capacities that correspond to those of the sensor branches. By comparing the number of charge transfer processes required to reach the switching threshold in the sensor branch and the reference branch, fluctuations of the supply voltage, and consequently the switching threshold itself, can be compensated for.

Abstract: An electric circuit for capacitive sensor elements of a touch switch can be designed as a switch capacitor circuit and van be provided with a micro controller. The sensor elements are provided in sensor branches with a charging capacitor. In addition, a reference branch is provide. It contains a reference capacity and a reference charging capacitor, which have capacities that correspond to those of the sensor branches. By comparing the number of charge transfer processes required to reach the switching threshold in the sensor branch and the reference branch, fluctuations of the supply voltage, and consequently the switching threshold itself, can be compensated for.

Abstract: The invention provides a device (11) for switching an electric heater (12) with at least two heating areas (25, 27, 29), which can be variably supplied with electric power by at least one power setter (22) and having control means (19) for the at least one power setter (22, 23) and with functionally separate switching means (14, 16) for operating the at least one power setter. On operating a first switching means (14), a heating area (27) associated therewith can be set by means of a power setter via the control means and on operating a further switching means (16) a heating area (29) associated therewith is settable by means of a power setter. Preferably, precisely one heating area (27, 29) is associated with each switching means (14, 16). The heating areas can be areally extensive heating zones or different power levels of a heater.