Abstract: A lighting system comprising lighting units each provided with a lamp and a control device for controlling the luminous fluxes of the lamps. The control device includes a first adjustment device (II) for selecting a lighting mode of the lighting system and a further adjustment device (III) for changing a desired luminous flux value in a chosen location illuminated by at least one lighting unit of a first group of the lighting units within a lighting mode. The system is also provided with a correction device (IV) for automatically changing the luminous fluxes of the lighting units of a second group of lighting units dependent upon a change in the desired luminous flux value at the chosen location. In the case of a change in the task lighting by the user (the luminous flux of a first group of lighting units), the surround lighting (the luminous flux of the second group of light units) is changed so that a good harmony between task lighting and surround lighting is maintained.

Abstract: A series section metallized film capacitor in which the metal layers are varied in thickness such that high oxidation areas are thicker than low oxidation areas. In particular, the edge portions bordering a center margin electrode gap have a thickness which is greater than the remaining area of the center margin electrode. The increased thickness at the edge portions reduces the oxidation effect and the associated decrease in capacitance which normally occurs due to the electric potential across the gap. By varying the thickness, the oxidation effect at the edge portions is reduced while the self-healing capabilities at the low oxidation areas is maintained.

Abstract: A ballast for lighting a high intensity discharge lamp having a power factor correction scheme. The power factor correction scheme includes a triac. To prevent the triac from damage when the lamp is not lit and power line transients are present, the triac is turned ON. The triac is also turned ON whenever the lamp is lit.

Abstract: A circuit arrangement for operating a high-pressure discharge lamp such that the high-pressure discharge lamp supplies a luminous flux of at least 60% of the nominal luminous flux within 1 s after ignition. The circuit arrangement is made up of a static converter for generating a DC voltage, a commutator provided with lamp connection terminals, a circuit for current stabilization during stable lamp operation by control of the static converter, and a circuit responsive to an instantaneous lamp voltage signal for operating the lamp with an increased run-up current and an increased power as compared with nominal rated operation during a lamp run-up period. A further circuit is provided so that the operation at the increased power includes at least a portion of the lamp run-up period for transition to normal operation. During this portion the increased power has a falling characteristic with a time constant that is independent of lamp voltage.

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: An audio amplifier having a volume-dependent tone control which is inexpensive and hardly distorts the audio signal. A filter in the signal path of the audio amplifier determines the tone control at low volumes. The bass tones and possibly treble tones are then amplified to a greater extent than the mid-range tones. With an increasing volume, a continuously controllable amplifier stage increasingly compensates this tone control. To this end a linear feedback path is arranged across this amplifier stage, with a pole in or near the frequency range of the bass and mid-range tones.

Abstract: A ballast for lighting an auxiliary source of illumination whenever a primary source of illumination fails to ignite. The auxiliary source of illumination is effectively turned OFF by placing a short circuit thereacross whenever the primary source of illumination is lit. The short circuit is removed whenever the primary source of illumination fails to reach a predetermined level of illumination thereby permitting current to flow through and light the auxiliary source of light. The ballast also includes a power factor correction device for increasing the ballast power factor when the primary source of light reaches a predetermined level of illumination.

Abstract: A circuit arrangement is described for commutating a collectorless direct current motor without a commutation sensor, the motor comprising at least two windings (608, 609, 610), in which arrangement the motor current is caused to commutate from one winding to the next winding in the direction of motion of the direct current motor by a pulse-shaped shift signal (sh) which signal is derived from an induced voltage (ui) in the direct current motor reaching a reference voltage (Ur).Such a circuit arrangement is to be improved in that erroneous commutations with diode pulses having flat trailing edges are avoided.

Abstract: A single-phase reluctance motor is constructed so that either the rotor or the stator (or both) has poles in which there are areas of different saturation induction (thereby forming an asymmetric saturation characteristic in these poles), as a result of which an aligned position of the movable member becomes non-aligned at increasing excitation current and the movable member begins to move in a predetermined direction.

Abstract: The apparatus comprises a magnet system which is rotationally symmetrically arranged about a central axis (9) and which comprises a superconducting inner coil system (1) for generating a steady magnetic field in a measurement space (5) within the magnet system, and also comprises an outer coil system (7) which is arranged so as to be coaxial with the inner coil system and which is electrically connected in series therewith in order to shield the environment from the magnetic field generated by the inner coil system. The magnet system can be bridged by of a superconducting persistent current switch (33) and comprises a superconducting shunt (37) which bridges a pan of the magnet system which is situated between first and second connection points (39, 41).

Abstract: A high intensity discharge ballast having an ignitor which shuts off after a predetermined time period has elapsed. The ballast is sensitive to voltage dips in power line voltage and resets a timer whenever the power line voltage drops below a level sufficient for lighting a lamp load. Restart of the lamp load immediately following restoration of power line voltage is achieved without requiring that the power line voltage be removed from the ballast or otherwise reduced to approximately 0 volts before restart can be initiated.

Abstract: A mounting member for a line illumination comprises single ended compact fluorescent lamp and a plurality of double ended tubular fluorescent lamps arranged in line and mounted in pairs and with its cap located. The mounting member is a T-shaped, light transmitting body, in which respective parts of two pairs of lamp holders are mounted, back to back, remote from each other, so as to allow the compact fluorescent lamp to be accommodated there between.

Abstract: The invention relates to an electric motor with permanent-magnet excitation, particularly inside-rotor and outside-rotor motors, comprising motor sections (10, 20) which are movable relative to one another, of which the first motor section (10) forms a multi-pole excitation field in an air gap (1) by means of permanent magnets (11) and of which the second motor section (20) is a soft-iron yoke (21) having pole teeth (22) which project towards the air gap (1) and which carry excitation coils (23).

Abstract: The invention relates to a magnetic resonance examination apparatus, comprising a coil system for MR mammography which has a particularly attractive signal-to-noise ratio. It comprises a first coil system (11) which comprises conductor loops which are merely inductively coupled to one another and which are provided on the surface of a cylinder in parallel planes, one of the loops being connectable to an input (22) of a receiving device (20). It also comprises a second coil system (12, 13) which is constructed as a surface coil and which is arranged at the end face of the first coil system (11) and can be connected to a further input (21) of the receiving device (20).

Abstract: A circuit for igniting and operating a discharge lamp includes a DC-AC converter provided with a first branch coupled to a DC voltage source and including at least one switching element for generating an alternating current at a frequency f. A load branch is coupled to the first branch A and includes inductive means (L), capacitive means, and an inductor for coupling the lamp to the load branch. A control circuit switches the switching element at the frequency f and includes a resonant circuit of a further inductor and a further capacitor. An ignition voltage limiter includes a second branch coupled to the resonant circuit and comprising a series arrangement of a frequency-dependent impedance and a semiconductor element of varible impedance as a function of its control electrodes potential at its control. A third branch is coupled to the load branch and to the control electrode of the semiconductor element for influencing the potential of the control electrode dependent upon the lamp voltage.

Abstract: In order to minimize signal influences on the reference potential in a rail-to-rail amplifier arrangement this arrangement comprises a first differential amplifier which comprises a first and a second transistor whose emitters are coupled to a reference potential via a common first resistor, the collector of the first transistor forming the output node of the amplifier arrangement, a second differential amplifier to whose input side the input signal of the amplifier arrangement is applied, whose output side is coupled to the base of the first transistor of the first differential amplifier, and having an inverting input coupled to the output node of the amplifier arrangement, a first current mirror circuit having an input transistor to which a reference current is applied, having an output transistor which is formed by the second transistor of the first differential amplifier, and having the emitter side of both transistors coupled to a reference potential, and a second current mirror circuit to whose input si

Abstract: In switched-mode power supply circuits the switch is rendered conducting for a longer period (or more frequently), dependent on the load connected to the power supply circuit, so as to ensure that the transformer can transfer enough energy to the secondary side for charging the output capacitor to a sufficient extent. To ensure that the transformer can always supply all energy stored in the transformer to the secondary side, a demagnetizing detection circuit detects the demagnetization of the transformer. If the load decreases (for example, in standby operation) the on-time of the switch is reduced. However, this on-time may achieve a minimum value so that the power supply circuit no longer functions properly. To obtain an efficiently operating power supply circuit, both in normal operation and in a low-load state, the control circuit of the power supply circuit has at least two modes, i.e.

Abstract: A flyback converter including a first (6) and a second (8) switching transistor, a first (10) and a second (12) rectifier diode, and a primary winding (14) of a transformer, which parts are connected in a bridge arrangement. The first switching transistor (6) receives its drive by positive feedback via a secondary winding (30), a coupling capacitor (36) and a series resistor (38, 40). Upon commutation of the voltage on the secondary winding (30) the first switching transistor (6) is turned off, a discharge diode (44) providing a discharge path for the coupling capacitor (36) in order to achieve that the first switching transistor (6) is turned on more rapidly in the next switching cycle. However, the discharge diode (44) limits the cut-off voltage on the control electrode of the first switching transistor (6), so that turning off proceeds comparatively slowly. This effect is eliminated by a voltage source (46, 48, 52) and a further switching transistor (54) which is turned on upon commutation.

Abstract: The invention relates to a reluctance motor having a ferromagnetic stationary member (3) and a ferromagnetic member (5) which is movable relative thereto, which exhibit an air gap (4) between spaced-apart pole faces (3c, 5c) of salient pole parts (3b, 5b), one of the members being provided with excitation coils, which surround ferromagnetic cores (3a, 5a) providing a ferromagnetic coupling between the pole parts of this member, the ferromagnetic cores being dimensioned to have such cross-sections that during the magnetisation of these cores by the excitation current the cores are magnetically saturated at the same time as the salient pole parts.

Abstract: A circuit for high-frequency operation of a discharge lamp. The circuit includes a load branch provided with terminals for connection to the discharge lamp and with an electrode heating transformer having a primary winding and secondary windings. Each secondary winding is shunted by a branch comprising an electrode of the discharge lamp. At least one switching element generates a high-frequency current through the load branch from a supply voltage. A control circuit generates a control signal for rendering the switching element conducting and non-conducting at a high frequency. A dimmer circuit is coupled to the control circuit for adjusting the frequency of the control signal. Each branch shunting a secondary winding of the transformer also includes an inductive element and a capacitive element and has a resonance frequency which is different from the resonance frequency of the load branch.