Abstract: A circuit arrangement to control at least one valve includes at least one actuator with at least one positioning element adjustable between at least one first position and a second position. At least one driver unit activates the actuator and a control unit operates the driver unit. At least one air mass measuring device measures an air mass flowing through the valve. The control unit processes an output signal of the air mass measuring device. Valves, valve arrangements, seat comfort systems, and methods all use such circuit arrangements.

Abstract: A leaf spring arrangement, especially for connecting a pressure plate to a housing, comprises a plurality of adjacent leaf spring elements, where each leaf spring element has a first attachment area for establishing the connection the pressure plate, a second attachment area for establishing the connection to the housing, and a connecting area extending between the first attachment area and the second attachment area. At least certain areas of at least two of the leaf spring elements are spaced apart between their first attachment area and their second attachment area.

Abstract: A pressure plate assembly for a friction clutch includes a housing arrangement and a pressure plate arrangement, which is held by at least one leaf spring arrangement with freedom of axial movement relative to the housing arrangement. The at least one leaf spring arrangement is fixed by a first attachment area to a first fastening area of the pressure plate arrangement and by a second attachment area to a second fastening area of the housing arrangement. The end area of the first fastening area and/or the second fastening area curves away from the minimum of one leaf spring arrangement, this end area being located in the area along which the at least one leaf spring arrangement extends.