Abstract: A method for measuring the diameter of an elongated article approximately circular in cross section, in particular of a wire or of a cable, which may include some or all of the following: illumination of the article with a fan-shaped beam of at least one monochromatic light source approximately point shaped in the measuring plane, wherein the main beam direction stands preferably perpendicular on the longitudinal axis of the article receiving the light on a single or multiple lined light-sensitive sensor on the oppositely lying side of the article, wherein the axis of the sensor stands preferably perpendicular on the main beam direction measuring the distance of the article to the sensor or the light source determining a value corresponding to the article diameter by evaluating the intensity patterns in the diffraction patterns at the edges of the shadow caused by the article, and of the measured diameter the distance of the light source to the article or of the sensor to the article is selected such that

Abstract: The device for measuring the capacitance of electrical wires has a first and a second measuring tube both connected to a voltage source of high frequency. The first measuring tube has a conventional length while the second measuring tube is significantly shorter. With the first measuring tube the capacitance of the wire can be measured in a conventional manner. The second measuring tube allows the measurement of local changes of the capacitance.

Abstract: A device for measuring the position of a conductor in an enveloped cable, preferably directly after extruding the plastic envelope, in which at least a supporting means for a sensor is continuously engaging the periphery of the envelope and in which the sensor determines the distance between the conductor and the sensor, and wherein the output signal of the sensor is delivered to a processing and displaying means, wherein the supporting means is defined by a roller driven by the cable which roller is yieldingly supported normal to the rotational axis.

Abstract: An apparatus for measuring eccentricities of a rod of plastic material extruded from an extruder includes an optical sensor arrangement having a central axis, the arrangement including a pair of optical sensor devices circumferentially spaced at 90 degrees to one another about the central axis and a pair of light sources disposed on sides of the central axis opposite to the respective optical sensor devices for providing shadows of the rod on the optical sensor devices. A mounting fixture supports the sensor arrangement with its central axis aligned with the nozzle axis of the extruder so that the extruded rod will travel along the central axis of the sensor arrangement. An output device is connected to the sensor devices for measuring deviations of the shadows from predetermined positions indicating concentricity of the rod.