Abstract: A piezoelectric actuator, which has a large displacement rate and a relatively simple structure, is capable of providing an output without the need for a specific support and can be manufactured at low costs, is provided. The piezoelectric actuator 10 takes a planar plate-like form and has first and second layer regions 11 and 12 lying one upon the other. The first layer region 11 is formed comprising a piezoelectric ceramic material and contains electrodes 13-1 to 13-n for receiving an actuation voltage to cause this first layer region to contract in a plane parallel thereto. The second layer region 12 is formed integrally with the first layer region 11 and comprises a ceramic material.

Abstract: A circuit arrangement for igniting and operating a discharge lamp (La), provided withinput terminals (K1,K2) for connection to a DC voltage source,a commutator (COM) coupled to the input terminals and provided with terminals (K3,K4) for connecting the discharge lamp (La), for cornmutating a current through the discharge lamp (La),a branch A which is conducting in both directions at least for alternating current, of which branch a first end is connected to an input terminal (K2) and a further end is connected to the commutator (COM), and which branch comprises an inductive element L shunted by a branch B which comprises a unidirectional element (D),a branch C which connects a further input terminal to the commutator (COM), andan ignition circuit (S) for igniting the discharge lamp. According to the invention, the unidirectional element (D)is so included in the branch B that the branch B conducts a current at least immediately after ignition of the discharge lamp (La).

Abstract: An electrodynamic device such as an electric motor has a stator (16) comprising a substrate (41) in the form of a sheet or foil carrying a plurality of windings (U.sub.1 -U.sub.3, V.sub.1 -V.sub.3, W.sub.1 -W.sub.3) comprising spiral coils (43, 45) on its upper and its lower side connected in series with one another, which stator has a number of phases (U, V, W) each comprising at least one winding. The device in accordance with the invention may comprise one or a plurality of such substrates (41), but each substrate always carries all the phases (U, V, W) present.

Abstract: A power semiconductor device circuit has an insulated gate field effect power semiconductor device with first and second main electrodes and a gate electrode. A gate control circuit provides a conductive path between the gate electrode and a gate voltage supply terminal. The gate control circuit has a resistance coupled between the gate electrode and the gate voltage supply terminal. A switching device has first and second main electrodes coupled to the gate voltage supply terminal and the gate electrode, respectively, so that the main current path between the first and second main electrodes is coupled in parallel with the resistance, the switching device having a first non-conducting state and a second conducting state for providing, in the second conducting state, an additional resistance in parallel with the resistance.

Abstract: A small motor having a two-pole permanent-magnet rotor and a U-shaped laminated stator having a pair of limbs with end portions that form magnetic poles for the rotor. The limbs carry alternately energized exciter coils including three nested winding layers arranged in two winding groups, of which the outer winding layer and the inner winding layer of the first limb and the second limb, respectively, and the central winding layer of the second limb and the first limb, respectively, are connected in series with one another.

Abstract: As rf quadrature coil system for a magnetic resonance examination apparatus, comprises two similar rf coils connected to an rf receiver and/or an rf transmitter and arranged so as to be offset 90.degree. with respect to one another. Each rf coil comprises several turns which are situated in mutually parallel planes. The planes of the turns of one rf coil extend perpendicular to the planes of the turns of the other rf coil. The quadrature coil system can be used in magnetic resonance examination apparatus in which the uniform, steady magnetic field required for the examination extends perpendicular to the longitudinal axis of the patient to be examined.

Abstract: An electrical connecting device having a receptacle and a two part plug inserted into the receptacle. The two part plug includes an inner part for holding a plurality of zero gap insulation displacement connectors and an outer part for receiving a corresponding plurality of insulated wires. The inner part of the plug can be inserted partially or fully within the outer part of the plug. When the inner plug part is in its partially assembled position, the insulated wires can be easily inserted into the outer part of the plug. When in its fully assembled position, the plurality of connectors within the inner part of the plug are in electrical contact with the insulated wires.

Abstract: A motor drive circuit for driving an electromotor having a permanent magnet rotor and a stator comprising one or more stator windings. When the supply voltage of the motor drive circuit fails, an emergency signal is generated by a signal generator. This emergency control signal activates an auxiliary power supply circuit for extracting electric energy from the motor and supplying the extracted energy to an auxiliary circuit. The auxiliary power supply circuit comprises a rectifier circuit formed by the fly back diodes bridging the switches of an electronic commutation circuit. The drive circuit comprises short-circuit switches bridging the stator windings. In response to the emergency control signal a short-circuit apparatus causes the stator windings to be temporarily intermittently short-circuited. As a result, a capacitor is charged. The energy stored in the capacitor is used for temporarily energizing the auxiliary circuit once the power supply to the drive circuit has failed.

Abstract: An electrical connecting device having a receptacle and a two part plug inserted into the receptacle. The two part plug includes an inner part for holding a plurality of zero gap insulation displacement connectors and an outer part for receiving a corresponding plurality of insulated wires. The inner part of the plug can be inserted partially or fully within the outer part of the plug. When the inner plug part is in its partially assembled position, the insulated wires can be easily inserted into the outer part of the plug. When in its fully assembled position, the plurality of connectors within the inner part of the plug are in electrical contact with the insulated wires.

Abstract: The accuracy of an apparatus for the movement of an object is increased by means of compensating for geometric errors and load and temperature induced deformations. The effects of the errors and deformations are stored in regularly updated compensation tables or parameterisations from which the error values as a function of position are available. The appropriate error values are selected while the complete momentary state of the apparatus can be taken into account. The derived error values can be used to correct the measured position in a feedback loop or to modify the steering signals for driving means without use of a feedback loop.

Abstract: A system for controlling the intensity of a lamp including a remote sensing device for detecting the presence of an occupant within an area. The device also transmits a signal based on the currently sensed presence of the occupant. After each transmission of an occupancy signal, the device is inhibited from further transmission for a first predetermined period of time to limit power consumption requirements by the battery powered device. The system also includes a light controller responsive to the transmitted occupancy signal for controlling the level of illumination by the lamp. In the absence of a transmitted occupancy signal within a second predetermined period of time, the light controller will instruct the ballast to reduce the level of illumination by the lamp. In the absence of an occupancy signal being transmitted within a third predetermined time period, the light controller will instruct the ballast to turn off the lamp.

Abstract: The invention relates to a device for driving the rotary anode of an X-ray tube, which device comprises a drive motor (5) having a stator (5a) and a rotor (5b), which are operated at anode potential, a rotor shaft (6) driving the rotary anode (7), the rotor (5b) of the drive motor (5) being constructed as an external rotor and the motor (5) being powered by means of a potential-isolating transmission means.

Abstract: A circuit arrangement for preheating electrodes of a discharge lamp connected in series with a ballast by means of a supply voltage of alternating polarity. The circuit arrangement is provided with a switching element (S) which shunts the lamp and which is operated by means of a control signal. A circuit portion (II) adjusts both the phase and the frequency of the control signal in dependence on whether the ballast is inductive or capacitive. The electrodes of the lamp are preheated in a short period both for an inductive ballast and for a capacitive ballast.

Abstract: In a film scanner for optically scanning a film for obtaining a picture signal, which film is moved at a constant speed, an image position correction which is as motion-independent as possible, is ensured in that the film scanner at least doubly scans at least parts of each film image and determines image position errors by comparing the two scanning signals of the same nominal image content, and corrects the picture signal in dependence upon the determined image position error.

Abstract: A power supply circuit for generating a stabilized power supply generally comprises a series arrangement of a primary winding of a transformer and a switch. The switch is controlled by a control circuit, an input of which receives a signal related to the output voltage of the power supply circuit. The control circuit determines the duty cycle of the switch. Dependent on the power consumption of the lead connected to the output of the power supply circuit, the duty cycle is either increased or decreased. The duty cycle has a given minimum value which is caused by the inertia of the switch upon switching on and switching off. The minimum duty cycle may be reached, inter alia, when the power supply circuit works in an apparatus using a standby mode.

Abstract: The invention relates to a method of generating a pattern of depressions in the surface of a workpiece, in particular one made of molybdenum or a molybdenum alloy for rotary-anode X-ray tubes. Such a method can be arranged in a more inexpensive and/or more environmentally friendly manner in that the workpiece is heated spotwise by a laser beam, the heating spot being directed over the surface in accordance with the pattern of depressions, in that a jet of oxygen is directed at the heating spot, and in that the energy supply to the heating spot is so controlled that the melting temperature of the workpiece material is not reached, while nevertheless the sublimation temperature of the oxide formed by the heating is exceeded.

Abstract: An electric lamp is provided which includes a reflector typically made of glass or metal and having a reflecting surface in which an area is formed to fit a locating device attached to the internal capsule light source. At the rear of the reflector is a neck portion in which are located several seating points for the light capsule locating device. Electrical connectors extend between the capsule and the base member. The positioning member is definitely located by seating ledges molded into the neck of the reflector. In manufacture, the positioning member is placed in tension and the lead wires for the lamp assembly extend through eyelets in the base which are then mechanically fastened so as to maintain a tension on the positioning member. The fact that the positioning member is under tension allows it to maintain positional accuracy during the life of the lamp.

Abstract: An electromechanical displacement device (81) provided with a holder (90), an element (45) displaceable relative to the holder (90), and an actuator (83) connected to the holder (90) by which the element (45) can be displaced relative to the holder (90). The actuator (83) is provided with at least a first and a second clamping member (B, A) which can be clamped alternately against the element (45) under a mechanical pretensioning force F.sub.k, at least one clamping member (A) being provided with at least one piezoelectric, electrostrictive or magnetostrictive clamping element (61). The actuator (83) is further provided with a piezoelectric, electrostrictive or magnetostrictive transport element (69', 69") by which the distance between the clamping members (A, B) can be changed. When the first clamping member (B) is clamped against the element (45) under the mechanical pretensioning force F.sub.

Abstract: A differential voltage-current converter has two input transistors and two cross-coupled transistors arranged in a translinear loop, the difference voltage across the emitter resistors of the cross-coupled transistors being equal to the difference voltage across the input terminals. The difference current through the cross-coupled transistors is replicated in the output transistors, thereby enabling a larger output signal amplitude to be obtained. In order to increase the permissible input voltage the bases of the cross-coupled transistors are coupled to the input transistors via emitter-followers. By connecting the collectors of the emitter-followers to the collectors of the output transistors a compensation is obtained for the decreasing current gain at high frequencies.

Abstract: A lamp driving circuit having a series inductor and capacitor (L-C) in which the lamp load is connected in parallel with the capacitor. During pre-ignition of the lamp load, the driving signal supplied by a half-bridge oscillator includes a fundamental frequency and a third harmonic of the fundamental frequency. The resonant frequency of the series connected L-C circuit is at least .sqroot.5 times greater than the fundamental frequency but less than the third harmonic of the driving signal.