Abstract: The invention relates to an electrical circuit (1) comprising an electromagnetic relay (4) and a switching arrangement (5), the outputs (A1, A2) of said switching arrangement being mounted in parallel to a contact (4a) of the electromagnetic relay (4). A control system (2) is connected to the coil (4b) of the relay (4) and the switching arrangement (5). The aim of the invention is to create one such circuit in a relatively interference-free manner. To this end, a voltage detection unit (6) is arranged between the control system (2) and the coil (4b). A first switching signal (S1) is produced, at a switching-on command, by means of a control unit (7) which is arranged downstream from the voltage detection device (6), said signal short-circuiting the outputs (A1, A2) of the switching arrangement (5). At the end of the switching-on command, the outputs (A1, A2) of the switching arrangement (5) remain short-circuited until the contact (4a) of the relay (4) is opened.

Abstract: The invention relates to a system for transmitting binary signals over a signal line to a signal detecting device, in which a DC source is temporarily connectable to the signal line for generating binary signals. A discharge circuit is connected to the signal line. In order to keep the power loss very low in such a system, discharge circuit (7) contains a switchable current sink (8) connected to a signal line (3). Discharge circuit (7) also has a threshold value determination device (19) connected to signal line (3) in parallel with switchable current sink (8). Output (26) of threshold value determination device (19) is connected with a control input (17) of switchable current sink (8).

Abstract: An arrangement for measuring the pressure in a cylindrical cavity by measuring the expansion of the cylindrical cavity in the circumferential direction which results from the pressure within the cylindrical cavity. Such circumferential elongations are measured by a first electrical transducer which is responsive to elongations in the circumferential direction. Contractions in the circumferential direction which results from elongations in the longitudinal direction of the cylindrical cavity are compensated by measuring such longitudinal elongations with at least one further electrical transducer. Such longitudinal elongations may result from bending or tensile stresses. The sensitivity of the electrical transducer for measuring the longitudinal elongations corresponds to the sensitivity of the electrical transducer which measures circumferential elongations, multiplied by the reciprocal of the Poisson ratio.