Abstract: A system that is adapted for determining the delay time between an initiating event and a response to that event. The system includes an optical sensor which is preferably a photo resistor having a resistance inversely proportional to the intensity of a warning light in its proximity. The output of the photo resistor is an analog signal that can be fed to an analog input device such as a strip chart recorder for display versus time. The initiating event signal can also be displayed so that, by comparing the signals, the delay between the initiating event and the changing of the warning light from off to on can be measured and compared to a specified value.

Abstract: Apparatus for extruding a first layer of a semi-conductive plastic material around the conductor of an electric power cable and for extruding a second layer of plastic insulating material around the first layer as the conductor is advanced in which the extruder for the insulating material includes an extrusion head which comprises a body with a passageway therethrough for the passage of the conductor through the body and having at least one channel therein extending from the exterior thereof to adjacent one end of the passageway for supplying the insulated material around the conductor. An extrusion tip or tubular guide is disposed in the passageway for guiding said conductor and extends across part of the channel for contacting material exiting from the channel. The guide comprises a ceramic tube with a polished inner surface forming the innermost surface of the guide.