Abstract: An operating device with haptic response for the manual entering of information into a device comprises a setting member having a position which is variable under the action of an actuating force, and with which there is connected a transducer for producing electric signals which characterize the position of the setting member. There is connected with the setting member a braking element which, under control by the electric signals, exerts a force on the setting member, the value of which force depends on the position of the setting member. The braking element has at least two surfaces which are movable relative to each other and between which there is provided a force transmitting fluid the transmission properties of which can be varied by the electric signals.

Abstract: A device for electrically measuring the level of a liquid in a container has a protective tube (1) in which a conductive foil (5) is arranged untwisted. The protective tube (1) is made of two tube sections (2, 3) which are connected to each other by a joint (4). The joint (4) has a well-defined direction of bend as a result of reinforcing ribs (14, 15). This direction is such that the protective tube (1) can be bent only transverse to the plane of the conductive foil (5). The joint (4) is furthermore so developed that the tube sections (2, 3) are urged into a position in which they are aligned with respect to each other. In this way the device can be installed in a container in such a manner that the lower tube section (3), while forming an obtuse angle with the upper tube section (2), has its bottom end resting against a container bottom (16).