Abstract: A photocoupler device with an insulating element comprising a shield situated perpendicularly to the optical axis of a light emitter and a receiver. The shield comprises a thermoplastic transparent material.

Abstract: A mechanism is provided for varying the distance between a detector and a measuring crystal in an X-ray spectrometer. The crystal is arranged on a rotatable shaft and the detector is arranged on an arm which can perform a circular movement about the crystal shaft. The crystal shaft and the detector arm are coupled so that a rotation of the crystal shaft through an angle .theta. is accompanied by a rotation of the detector arm through an angle 2.theta.. A first pulley having a radius r is mounted on the crystal shaft and a second disc having a radius 2r is rotatably mounted on the crystal shaft. A belt or cord is guided over each one of two guide rollers. One end of each of these belts is permanently connected to the first pulley, while its other end is permanently connected to the second pulley.

Abstract: By using a optical switch, which can be operated by the tuning knob of a receiver, signals can be obtained which accurately correspond to the operation of the tuning knob for switch-over of the receiver to a continuous manual tuning mode and for suppressing the automatic tuning correction during tuning.

Abstract: A television pick-up device suitable for a discontinuous recording of information during continuous operation, such as, for example, in X-ray television. When information recording is interrupted at a continuing field scanning of a target plate in the pick-up tube, the cathode thereof is supplied from a supply circuit with a higher voltage than during the field scanning during information recording. As a result thereof a negative charging of the free surface of the target plate by the more rapid electrons in the electron beam is prevented, so that at the next recording of information the picture quality on display is not poorer due to signal clipping.

Abstract: A loudspeaker combination comprising a plurality of sections of dynamic loudspeakers which are arranged adjacent each other in substantially one continuous plane. A number of these sections can be muted at increasing frequency under the influence of a low-pass filter. All loudspeaker sections are connected in series with each other and each mutable loudspeaker section is shunted by a capacitor. Each low-pass filter is constituted by the impedance of a mutable loudspeaker section with the associated capacitor. One loudspeaker section is not shunted by a capacitor and comprises at least two loudspeakers with the axes of the loudspeakers diverging relative to each other. This has the advantage that the loudspeaker combination has a virtually constant angle of aperture over a wide frequency range.

Abstract: A field effect transistor of the V-MOST type in which the channel region comprises a more highly doped part which adjoins the source zone and a lower doped part which surrounds said region, said channel region adjoining the surface and surrounded by an insulation diffusion. The lower-doped part is depleted from the pn junction with the low-doped drain region up to the surface at a voltage which is lower than the breakdown voltage.

Abstract: An equalizing network for attenuation/frequency characteristic equalization. The equalizing network comprises a plurality of attenuation branches B.sub.1 to B.sub.8 which are operative in mutually different frequency sub-bands covering a wide frequency band. A negative feedback amplifier 10 has its negative feedback factor set for each frequency sub-band by means of a potentiometer P.sub.1 to P.sub.8 which is part of the relevant attenuation branch. Resistors 17, 18, 19 and 20 form the negative feedback circuit for the amplifier 10 and provide voltage-dividing, to alter the feedback factor and thus the gain of the amplifier 10, for the individual frequency sub-bands as determined by the potentiometer settings. Attenuation branches pertaining to non-adjacent frequency sub-bands are grouped together in two groups X and Y to obviate the need for separation amplifiers for each attenuation branch.

Abstract: A device for measuring blood pressure comprising a circuit having two signal paths one of which can guide the alternating current components and the other of which can guide the direct current component of the blood pressure signal, said signal paths comprising amplification and/or attenuation members so that the mutual ratio of the alternating current components and the direct current component is varied. The device furthermore comprises a summing device to recombine the two previously treated parts of the blood pressure signal and an amplifier or attenuator to make the overall amplification of the direct current component (average value) equal to unity.

Abstract: An apparatus to collect contaminants from a known volume of fluid and to present the collected contaminants for analysis. The apparatus has a first container to receive the known volume of fluid and a second container to receive the fluid from the container. A contaminant trapping material is located between the two containers so that as the fluid passes from the first container to the second container it passes through the contaminant trapping material. The second container is connected to a vacuum generator used to create a vacuum in the second container. The apparatus also has means to recirculate the fluid from the second container back to the first container so that the fluid can pass through the contaminant trapping material a given number of times thereby insuring an adequate collection of contaminants. A method of collecting contaminants from a fluid and presenting the contaminants for analysis is also disclosed.

Abstract: A four channel stereophonic sound system requiring only two transmission channels and two audio amplifiers is disclosed wherein two different linear combinations of all four original discrete signals are recorded or transmitted, amplified and subsequently decoded in a passive network interconnecting the four output speaker system.