Abstract: A PC board to be populated with electronic components, for insertion into the housing of an electronic device, has a core made of two metal plates connected together and spaced apart by reinforcing ribs, said plates being provided with a copper-invar layer and with a cover layer formed by several layers of polyimide film. To achieve high rigidity and good heat transfer, the metal plates are made of aluminum or an aluminum alloy and are fastened in the housings by means of gibs and cotters.

Abstract: A capacitive measuring system for measuring the distance between two relatively movable parts based on measurement of capacitative charge comprising a measuring sensor which forms one plate of the capacitor whose gap is to be measured. With the position of the sensor face in the fixed part of casing being known, the plate distance of the gap capacitor provides a direct measure of the gap.

Abstract: A capacitive measuring system including a sensor for measuring the clearance between a movable part and a fixed casing facing the movable part, the sensor is secured in the casing and has an active face facing the movable part to constitute a capacitor whose charge is representative of the clearance. A triaxial cable connects the sensor to an amplifier. The triaxial cable has a central conductive core and two surrounding conductors insulated from one another and from the core. The sensor comprises a central body including a disk with a surface constituting the active face of the sensor made from a metal of the platinum group (VIII) or an alloy thereof. The central body is connected to the core of the triaxial cable. Two conductive shields surround the central body and are connected to respective conductors of the triaxial cable. An electrical shielding or insulation of ceramic or glass is between the central body and the conductive shields.

Abstract: Method and apparatus for optical measurement of fluid flow in which particles are injected into the fluid flow to permit accurate velocity measurements to be made thereof between two laser beams through measuring windows and to obtain a velocity profile. One beam is fixed and provides indication of start event, and the other beam is moved in discrete angular steps around the first beam in oscillatory fashion to provide indication of stop events. The sum of the particles passing the start beam and the sum of the particles subsequently passing the stop beam are correlated by electronic evaluation circuitry.

Abstract: A method and apparatus for measuring pressures in a gas turbine engine comprising a stator, a hollow rotatable shaft carrying a rotor and a first sensor having a plurality of inputs for pressure measured at respective test points on the rotor.