Abstract: A switch device (1) and its operation from an actuation side (51) are disclosed, the switch device having a plate-shaped main body (10), a plate-shaped actuation part (20), a connection device (30) located between the main body (10) and the actuation part (20) made from an elastic material, and at least one sensor (41, 42, 43, 44), which are located between the main body (10) and the actuation part (20) and viewed in the thickness direction (Z) are located at the side of the connection device (30), so that each sensor (41, 42, 43, 44) can be used to detect a position of one region, arranged on said sensor, of the second surface in the thickness direction (Z).

Abstract: A control circuit for controlling an electron-emitting device is formed to draw, with a voltage applied, an excitation current being related to a number of electrons emitted. The inventive control circuit includes a first determinator for determining whether an amount of charge transported by the excitation current has reached a predetermined charge threshold value, a second determinator for determining whether a magnitude of the excitation current has reached a predetermined current threshold value, and a switch for switching off the excitation current as soon as the first determinator determines that the amount of charge has reached a predetermined charge threshold value, or as soon as the second determinator determines that the magnitude of the excitation current is smaller than the predetermined current threshold value.