Electrical sensors; sensor modules for positioning on holding modules; holding modules for holding sensor modules; holding modules for holding sensor modules, said holding modules with electrical connections and/or signal connections; positioning switches and positioning sensors; multiple limit switches; inductive, optoelectronic, capacitive, and magnetic field dependent proximity sensors and switches; distance sensors, distance switches; rotational signal transmitters; shaft encoders; displacement transducers; ultrasound sensors; sensors adapted to be coupled to electrical buses; signal evaluation sensors and circuits for measuring object positions, paths, rotational speed, angular position, velocity, acceleration and time; interface converters for electrical buses, sensors, transmitters and commutators; identification sensors and circuits; path measurement sensors and circuits; precision switches and switching circuits; electromechanical switches; detectors and detector bodies for sensors and commutators; sequence signal cams, cam strips and cam racks for electrical detectors; couplers and connectors for electrical cables; couplers and connectors for electrical circuits; sensor holders