Abstract: An apparatus and method for recharging a rechargeable battery in a hand-held transceiver while maintaining communications capability through the transceiver. The battery charger is housed in a charging unit to which the transceiver can be removably attached. A dual-mode charging circuit generates a first voltage during transmit mode and a second, higher voltage during receive mode, and includes a DC-DC converter for generating the second voltage. The charger includes a push-to-talk (PTT) switch and mode control circuitry for simultaneously controlling the operating modes of the charger and transceiver, and additionally includes a separate microphone, speaker, and audio and RF amplifiers for providing greater RF power and audio power while the transceiver battery is being recharged.

Abstract: Apparatus for holding a series of permanent magnet rotors having parallel transversely spaced coplanar rotational angles firmly at any of a wide range of desired angles without consumption of energy, the angles being linearly adjustable independently of rotor spacing and with constant torque sensitivity, by mechanically linking each rotor to an adjacent rotor to form pairs and arranging the magnetic axes mutually perpendicular and perpendicular to the axes of rotation, coupling each rotor to a direct magnetic control field component perpendicular to the plane which is common to the rotor axes and varying the amplitude ratio of the field components coupled to the rotors of a linked pair according to the tangent of a control angle to turn the rotors through a corresponding angle.

Abstract: The invention relates to magnetizing apparatus for the magnetization with coded orientation of magnetic blades (6) to be embedded into two sides of a magnetic key shank forming part of a magnetic safety lock system, wherein tapering flux-conducting soft iron shanks (2, 4) are coupled to the poles of an exciting magnet (1) of the apparatus. Between the shanks is an air gap (3) into which a feeding mechanism feeds the blades (6) to be magnetized.The magnet is a permanent magnet (1) made of intermetallic compounds of rare earth metals of shell 4f with transition metals of shell 3d by means of powder metallurgy or casting. The areas of the soft iron (2) which are contiguous to the air gap (3) are made of a material of high saturation value. The direction of the feed of magnetic blades (6) is parallel with the direction of the magnetic field (dipole) of the poles of the flux-conducting soft iron (2).

Abstract: A DC/DC converter for producing a plurality of output voltages, comprising a transformer having a primary coil and a plurality of secondary coils; a switching circuit adapted to turn ON and OFF the supply of input DC voltage to the primary coil; rectifying and smoothing circuits for rectifying and smoothing the AC voltages obtained in the secondary coils; a circuit means connected in series with the rectifying and smoothing circuits to obtain the sum of the output voltages from the respective rectifying and smoothing circuits; and a control circuit adapted to receive the lowest DC output voltage from the rectifying and smoothing circuits and to control the ON - OFF operation of the switching circuit so that the lowest voltage is maintained at a constant level, and wherein the DC voltages from the respective rectifying and smoothing circuits are obtained by making use of one of the output terminals of the lowest DC voltage as a common terminal.

Abstract: In the control apparatus of an AC/DC power converter, the occurrence of a single-phase line-open in the AC power line is detected by an open-circuit detector so that a detection signal is generated. The control angle of a converter on the side of occurrence of the single-phase line-open is kept at a given value based on the detection signal. At the same time, the current set value of the automatic current regulator is also kept at a fixed value based on the detection signal.

Abstract: A battery charging device which is so designed that whether or not the battery is connected in position can be detected by utilizing a current detecting circuit instead of a mechanically-structured component, such as a switch.

Abstract: A digital power converter input current control circuit is connected between a power converter and a power source. This circuit monitors, and controls if necessary, the current that flows between the power source and the power converter in a manner that protects the power source, the input current control circuit, and the power converter from the catastrophic effects of excessive current flow. The input current control circuit operates similar to an electronic circuit breaker with an automatic reset feature, in that the power delivered to the power converter is maintained low during fault conditions. Thus, if a power transistor in the power converter should fail, a current limit circuit in the input current control circuit will prevent additional damage to the power converter.

Abstract: A system is provided for alleviating harmonic distortion in a power supply having an AC input, a full wave rectifier and filter capacitors. The rectified voltage is chopped at a frequency that is higher than the frequency of the original AC waveform. The higher frequency cycle is provided by timing means coupled to the gate of a FET. The chopped and rectified voltage is stored in an inductor device during one portion of the higher frequency cycle and the energy from the inductor device is transferred to the filter capacitors during another portion of the higher frequency cycle. A reverse protection diode, and a capacitor for delivering high frequency energy to the FET are connected across the output of the full wave rectifier.

Abstract: Disclosed is a circuit including an NPN transistor of which the collector is connected to a voltage output portion, the emitter is connected to a reference voltage portion, and the base is connected to the voltage output portion through a resistor providing a voltage drop across the base and the voltage output portion, circuit further comprises a pinch resistor connected in parallel to the former-recited resistor to make a reference output voltage Vref of the circuit have a predetermined reference value regardless of a current amplification factor .beta. of the output transistor.

Abstract: A 3-phase-to-3-phase power converter is intended to control the output voltage and current so as to provide a 3-phase sinusoidal wave which is controlled in compliance with the input voltage. The main circuit has a switching period shorter than 30.degree. of the power voltage waveform and it is controlled so that switching of lines takes place in alternate fashion, whereby the input power factor is improved.

Abstract: Static inverter with controlled semiconductor switches and anti-parallel diodes and with a control device for providing a current well above the rated current in the case of a short circuit in a consumer for quickly blowing a fuse in the circuit of the consumer. Anti-parallel thyristors are connected across the inverter output. The control device upon a short circuit takes over the control from the normal inverter control device and switches the semiconductor switches between two curents in the load circuit, of which the higher current represents the peak current limit for the semiconductor switches and the lower current lies considerably above the rated current. The control blocks the semiconductor switches when the current limit is reached and fires at least that thyristor which allows current to pass in the direction of the actual current flow.

Abstract: For recognizing the blocked state of a thyristor which can be switched off (GTO thyristor), especially also if it is alloyed through or the driver addressing the thyristor is defective, a state signal indicating the actual advent of the blocked state is generated after the occurrence of a turn-off signal, if the derivative in time of the gate current has exceeded a positive upper limit, which indicates that the thyristor has been turned off successfully. The maxima of the derivative in time of the gate current are almost independent of the actual anode-cathode current to be extinguished. The derivitive in time of the gate current is advantageously determined via a coupling inductance. Preferably, the method and apparatus are used with a mutual adaptive turn-on interlock of GTO thyristors in converter equipment and can be urged to release protective measures in time if permanent conduction (short circuiting) of a thyristor occurs.

Abstract: A vehicular battery charger connects with a battery powered portable radio via plural electrical contacts including a so-called "universal device connector" (UDC). A battery contact interface is also provided. Battery charging current as well as auxiliary radio operating power is made available at the contact interfaces. In addition, the charger is capable of remotely controlling the modus operandi of the portable radio device so as, if desired, to convert the portable radio device to provide vehicular mobile or fixed base radio operations during the battery charging process. If such modified radio operation is desired, the battery charger detects current being drawn from the external radio power supply source (for supplying power to the radio operating circuits independently of the portable radio battery which is then being charged) and automatically reconfigures the portable radio device as needed to effect the vehicular mobile or fixed base operation.

Abstract: A constant voltage generator includes a resistance adjustable resistor having a series connection of a main resistor and sub-resistors, a circuit cooperating with the series connection to produce a constant voltage, a plural number of transistors having a collector-emitter path connected to corresponding one of the sub-resistors, and a plural number of semiconductor memories applying voltages to bases of the transistors, respectively, in accordance with stored information, whereby the resistance of the resistance adjustable resistor is adjusted by the stored information to control the output constant voltage.

Abstract: An upper magnet and a lower magnet respectively above and below the objects to be degaussed/demagnetized. They are arranged with their fields mutually transverse, and both at 45.degree. angles to a conveyor carrying the objects between the magnets. Either or both magnets may be rotated, selectively, and they are rotated in opposite directions.

Abstract: A dual voltage, dual battery electrical supply system for automotive vehicles is disclosed. Two batteries are connected in series and a high voltage regulator regulates the voltage across the series connected batteries and a low voltage regulator regulates the voltage across the lower battery of the series connection. Overvoltage protection is provided for the lower battery by a control circuit which resets the high voltage regulator to a reduced voltage in response to a predetermined voltage across the lower battery.

Abstract: In order to produce direct voltages with greater flexibility, a rectifier (1) according to the invention comprises an alternating voltage measuring sensor (25), a comparator (22), controllable switches (160 to 183) and a switch control (20), through which the switching states of the switches are alterable in dependence on the output signal of the comparator, in order so to connect at least one of the direct voltage outputs (11, 12, 13) for certain time spans during each alternating voltage phase one after the other with the alternating voltage inputs of the rectifier that a pulsating direct voltage drops at it relative to a fixed or variable direct voltage potential. The switching instants are determined through constant measurement of the instantaneous alternating voltage values and their comparison with predeterminable direct voltage levels or alternating voltages, which serves as reference values.

Abstract: A battery charger circuit having a main transformer and a boost transformer. The main transformer supplies power to produce a DC main charging current at the circuit output for charging a battery. The boost transformer supplies power to produce a DC trickle charging current at the circuit output. The power rating of the boost transformer is a small percentage of that of the main transformer.

Abstract: A current-source power converting apparatus having a three phase AC-DC converter composed of self-extinction devices for converting an AC power furnished from an three phase AC power source into a DC power and a DC-AC inverter connected with the AC-DC converter through a DC reactor for re-converting the DC power into a three phase AC power to supply the re-converted power for a load. When the failure of the AC power source is detect according to one embodiment, the AC power source is detached from the AC-DC converter and a battery is connected between arbitrary two phases at the input end of the AC-DC converter. After that, the DC power of the battery is supplied for the DC-AC inverter intermittently by switching the corresponding self-extinction devices of the AC-DC converter and controlled by varying the duty ratio of the switching operation.

Abstract: A circuit for safely and rapidly charging batteries, with the charging occurring at three different rates. A first rate is used to bring a battery up to a level where it is determined to be safe for rapid rate charging. At this charge level the temperature of the battery may also be checked to be sure it is within a safe range for rapid charging. If safe, the battery is then rapidly charged at a second rate, until it is almost at its maximum capacity. At that point a third rate charge, lower than the first charge rate, is used to maintain the battery at nominally full charge. A microprocessor controller controls a plurality of rapid rate chargers and determines when the battery parameters are safe so that rapid charging can be safely employed. The rapid charger may be of a conventional charge pump type.