Abstract: A semiconductor light modulator is disclosed. The light modulator comprises a semiconductor body and a waveguide for guiding light rays formed in the body. The waveguide comprises waveguide sections of first and second types formed alternately in a series. Each waveguide section of the first type is delimited at least in part by a depletion zone. A voltage U may be applied for controlling the size of the depletion zone delimiting the sections of the first type to vary the ability of the sections of the first type to guide light. Illustratively, when the voltage U is near zero, the light confining characteristics of the sections of the first and second type are substantially identical, so that light rays are guided along the waveguide from one section to another.

Abstract: A device for use in connection with electricity meters incorporating current transformers is disclosed. The device detects saturation incidents of the magnetic cores of the transformers, thereby reducing measurement errors.

Abstract: An inventive Hall element formed from semiconductor material is disclosed. The inventive Hall element comprises a plurality of interconnected portions formed in a common semiconductor layer. Depending on how the portions are interconnected, the Hall element may detect the sum or difference of magnetic field values. The invention enables the realization of very large Hall elements which can be used in electrical meters to measure a magnetic field produced by an electric current.

Abstract: A driving device for controlling the driving frequency for a stepping motor includes a voltage control pulse generator for producing electrical pulses for driving the stepping motor. The pulse generator includes an RC network providing a time base for the pulse width and the operating frequency of the electrical pulses. The RC network includes at least one controllable resistance and a capacitor connected to control the controllable resistance by the charging and discharging of the capacitor.

Abstract: A method and apparatus for embossing a pattern having a microscopic relief structure, such as, for example, an optical diffraction grating, onto a layer of thermoplastic material is disclosed. A small circular region of a flexible embossing die is pressed against the thermoplastic layer by means of a punch. A fraction of the corresponding small circular region of the thermoplastic layer is then heated from the rear by a beam of radiant energy. The process may be repeated at all points on the thermoplastic layer where the pattern is desired.

Abstract: A circuit arrangement for the input circuit of a meter for simultaneously measuring two electrical quantities is disclosed. The circuit includes a current transformer including a primary winding, two substantially equal secondary windings and a pulse amplitude modulator associated with each secondary winding. Connections are made from each secondary winding to one terminal of its associated and non-associated pulse amplitude modulators, respectively. The circuit can be manufactured simply and economically while providing a high quality meter. Other embodiments provide additional advantages.

Abstract: A card, such as a credit card or identification card, includes electronic circuitry which permits its identification by an identifying device. More particularly, optical radiation is transmitted from the identifying device to the card to be identified. The radiation is modulated with information by a modulating device included in the card and is retransmitted to the identifying device.

Abstract: The present invention is an arrangement for measuring electrical power. The arrangement comprises a conductor traversed by an electrical current i and a voltage-to-current converter for transforming an electrical voltage u.sub.N into a proportional supply current i.sub.N for a Hall element. The Hall element is adapted to produce an intelligence containing output signal .+-.u.sub.H proportional to the product (.+-.i.u.sub.N) of the current i and the voltage .+-.u.sub.N. The Hall element is arranged in an air-gap of a ferromagnetic core that is excited by the current i. A voltage-to-frequency converter transforms the Hall element output voltage .+-.u.sub.H into a proportional output frequency. The voltage-to-frequency converter includes a capacitor for integration purposes and at least two signal sources. The power measuring device also includes a switch for periodically switching a signal proportional to the signal .+-.u.sub.H and for switching said signal sources to compensate for an offset voltage.

Abstract: A method and apparatus for converting an electrical signal into a proportional frequency is disclosed. Modulation of the output frequency resulting from polarity switching cycles having half-periods of unequal duration and capacitor voltages which might be non-zero at the time of polarity reversal are substantially avoided. This permits faster and more precise calibration.

Abstract: A security blank includes a sheet, and an elongated security thread connected to the sheet. The security thread may be identified upon being irradiated by electromagnetic radiation by a recognizable signature from radiation scattered therefrom; the cross-section of the security thread is other than circular or rectangular and is substantially constant over a prearranged portion of the length thereof.

Abstract: The present invention is an electrical circuit for use with a four-pole device. The four-pole device has two input connections and two output connections. The output of the four-pole device is measured at one output relative to a base potential present at the other output.The electrical circuit comprises a two-poled switch, which is connected in such a manner, that in its first position a signal source is connected with the first input of the four-pole device and the output of an amplifier is connected with the second input of the four-pole device. In the switch's second position, the signal source is connected with the second input of the four-pole device and the output of the amplifier is connected with the first input of the four-pole device. The output of the four-pole device, which is at the base potential, is connected to an inverting input of the amplifier, while the non-inverting input of the amplifier is connected to a constant reference voltage (U.sub.R).

Abstract: A magnetic field sensor having a lateral bipolar magnetotransistor incorporating only a single emitter region and whose base region is incorporated as a well in the surface of a silicon substrate of the reverse material conduction type. The P/N junction of the base region with the silicon substrate is reverse biased by means of at least one secondary collector contact. The emitter region must be kept as shallow than 0.5 .mu.m or be so lowly doped with impurity atoms that its resistivity is greater than 100 ohms per square or both. The sensitivity of the magnetic field sensor is approximately 100%/Tesla.

Abstract: The present invention is a one-phase stepping motor having a predetermined direction of rotation. The motor comprises a rotor having 2p permanently magnetized poles on its outer surface. The rotor is surrounded by a coil, which when energized forms the main stator poles. Auxiliary pole arms extend into the space between the coil and the rotor.The rotor and coil are stored in a two-part housing which magnetically isolates the motor. The auxiliary pole arms extend inward from the top and bottom surfaces of the housing and are formed integrally therewith.The arrangement of the auxiliary pole arms serves to determine the direction of rotation of the rotor. Illustratively, the auxiliary pole arms are divided into groups. Within each group, the auxiliary pole arms are at a distance from the rotor that decreases gradually or in stages in the direction of rotation of the rotor.This one-phase stepping motor is especially suitable for driving counting mechanisms in electricity meters.

Abstract: In a system for optical display and photo-electric scanning of the contents of a counter equipped with counting wheels, and wherein each counting wheel includes a plurality of numeral members visually distinguishable from the periphery thereof, a coded optical marking member is associated with each numeral member of a respective counting wheel. The coded optical marking member includes at least one optical surface element, and the optical marking members of the counting wheels extend along respective rows, and may be scanned by a light ray moving along a corresponding row. The improvement includes one of the members being superimposed at least in part onto another of the members in a corresponding row, and being partially light-transmitting, while each optical surface element is light-reflective, so that the numeral members are visible upon being illuminated with diffuse light, but wherein a light ray directed onto a respective optical surface element is reflected therefrom.

Abstract: A circuit including a magnetic sensing device for measuring magnetic fields is disclosed. The output of the magnetic sensing device is amplified by an amplifier and feedback to the magnetic sensing device. A potentiometer comprising two resistors R.sub.1 and R.sub.2 is connected between the output of the amplifier and ground. The feedback signal is taken from the common terminal of the two resistors. When circuit parameters are appropriately chosen, a magnetic field measuring circuit which is linearly responsive to changes in magnetic field intensity and relatively temperature independent results.

Abstract: A security element for authenticating bank notes, credit cards, security passes and the like is disclosed. The security element incorporates a reflective-type diffraction grating, which grating comprises a continuous layer of reflecting material on which is deposited a layer of dielectric material. Non-continuous reflecting layer portions are embedded in the dielectric material. It is practically impossible to lay bare the diffraction grating without destroying it.

Abstract: A method for forming and transmitting information carrying signals in an electrical power distribution network is disclosed. A step-shaped current signal is produced by switching at least two purely ohmic loads between a pair of power lines. The ohmic loads are switched between the power lines in accordance with a predetermined sequence so that a current signal having the desired waveform results. The step-shaped information carrying signal usually has a frequency which is higher than the power transmission frequency of the supply network.

Abstract: A stepping motor is disclosed, which includes an inventive arrangement of stator pole arms. The arrangement of stator pole arms has the effect of smoothing out the drive torque characteristic of the stepping motor.

Abstract: A circuit for providing temperature compensation to a Hall element is disclosed. The temperature compensation circuit is used to generate control signals which act on the effective thickness of the current channel of the Hall element in a manner so as to oppose changes in the effective thickness of the current channel produced by temperature variations.

Abstract: A current transformer equipped with a primary winding (1), a secondary winding (2), as well as a detector winding (3), has a rigid coupling between the secondary winding (2) and the detector winding (3). The coupling factor between these windings (2, 3) and the primary winding (1) is considerably smaller than one, since only one portion of the magnetic flux .phi..sub.1 created in the primary winding (1) by the current I.sub.1 to be measured is detected by the detector winding (3). This partial flux .phi..sub.13 is compensated by the flux which is created in the secondary winding (2) by means of a variable-gain amplifier.