Abstract: An output control circuit of a 4-burner electronics induction heating cook system comprises a unit for measuring the proportional setting time to selectively operate the timing on-off control and the frequency control of a heating load; an invertor circuit for generating a proportional time and applying this to the load; a current feedback/output adjusting circuit provided with a differential amplifier inputing a high or low level signal according to a signal from the current detector; an output setting control portion provided with a unit for comparing the signals from the circuit connected to the adjusting circuit and the saw tooth wave generating circuit and then outputing a pulse width modulation signal; an output setting control portion provided with at least one photocoupler wired in an OR configuration to control the operation of the control portion and a microprocessor connected to control the operation of the photocouplers; a base operating portion and a timing circuit for controlling an invertor cir

Abstract: A high-frequency heat source supplies a predetermined high-frequency heat output. An inverter circuit receives an AC input and supplies a high-frequency output to drive the high-frequency heat source. The inverter circuit includes a circuit for rectifying the AC input, and a switching element for switching a DC output from the rectification circuit. A timing circuit is coupled to the inverter circuit to detect a switching timing of the switching element to the inverter circuit. A controller outputs an ON/Off signal having a predetermined duty ratio corresponding to a heating output set value associated with the predetermined high-frequency heating output. The ON/Off signal is output at a predetermined timing in response to a detection output from the timing circuit. A drive circuit drives the switching element in the inverter circuit in response to the ON/Off signal output from the controller. A first isolation circuit electrically isolates the timing circuit from the controller.

Abstract: A pair of static induction thyristors, which are coupled in parallel in the opposite bias directions between an AC power source and a load, is turned on by a light signal and is turned off by natural commutation, a light signal or an electric signal. The turn-off light signal is generated within a phase angle of 90.degree. in the time axis around the zero-cross point of the AC voltage from the AC power source.

Abstract: A constant-voltage power supply circuit having a light-emitting element and a photosensitive element optically coupled with each other and a driving power source for driving the light emitting element, the circuit using an output voltage of the photosensitive element as a reference voltage; and an amplifier circuit using a constant current converted from the reference voltage of the constant-voltage power supply circuit; and a DA converter adapted for delivering binary digital signals to the constant-voltage power supply circuit.

Abstract: To reduce the cost of insulation in a high-voltage power supply capable of constant current or constant power operation, the power supply includes an optical self-powered feedback circuit from its high-voltage section to the low-voltage section to control the output of the power supply. The feedback circuit includes within the high-voltage section of the power supply: (1) a sensing circuit for obtaining an amplitude modulated signal related to current flowing through at least certain output terminals; (2) a voltage-to-frequency converter for converting the amplitude modulated signal to a frequency modulated signal; (3) a pulse shaper for generating pulses having a duration of less than 3 microseconds to reduce power consumption; and (4) a light emitting diode. Light from the diode is transmitted to a low-voltage section where it is utilized in the feedback network. The high-voltage feedback circuitry utilizes less than 75 microamps.

Abstract: A resistor has a resistance which is precisely controlled by means of a voltage control circuit. The controlled resistor is a radiation sensitive device which is optically coupled to a source of radiation connected to the output of an operational amplifier. A control circuit applies a controllable (preferably programmable) voltage, functionally related to a desired resistance of the controlled resistor, to the input of the operational amplifier. Also connected to the input of the operational amplifier is a feedback radiation sensitive resistor, which is also optically coupled to the radiation source. Preferably, the controlled radiation sensitive resistor and the feedback radiation sensitive resistor have substantially identical resistance characteristics. A compensation circuit is electrically connected between the input and output of the operational amplifier.

Abstract: Disclosed is a novel switching circuit directed to use for limiting surge into lamp, comprising a diode circuit wherein two sets of diodes are connected in reverse-parallel; a resistive element connected in series with a lamp to limit the switch-on surge thereinto; a bidirectionally conductive element having a main current path connected in seried with an ac source through said resistive element, diode circuit and lamp; and a timing circuit having a time constant, said timing circuit triggering said bidirectionally conductive element with the voltage across said diode circuit to short-circuit said resistive element after a lapse of said time constant from switch-on.

Abstract: A power supply circuit for generating two direct voltages. A preload, having a tap for deriving the second voltage, is arranged between the lead conveying the first voltage and a reference potential. To prevent mutual influences between the two voltages, the preload is in the form of a series arrangement of at least one resistor and a plurality of reverse-biassed semiconductor diodes, an abrupt change of the differential resistance occurring above a given value of the current through these diodes. A controllable semiconductor element for controlling the second voltage is incorporated between the tap and the lead conveying the second voltage. The first voltage may be an E.H.T. for a final anode of a picture display tube, the second voltage is then a focussing voltage for a focussing electrode of this tube.

Abstract: A power controller includes a full-wave bridge rectifier circuit coupled to an A.C. line by a storage inductor with two windings and a saturating inductor. The output of the bridge rectifier is connected to a D.C. output terminal for producing output voltages for a symmetrical amplifier. The D.C. potential provided by the full-wave rectifier is compared with a ramp signal having an external ramp set point related to the D.C. output potential relative to a reference potential to provide a trigger pulse for controlling the time the SCR is gated on. A balancing system selectively switches auxiliary resistances in and out to maintain a desired balance. Upon sensing a gross imbalance, the SCR is turned off. The power controlling apparatus includes isolation circuitry for creating an isolation barrier having a high frequency path and a low frequency path. The high frequency path includes a transformer having main primary and secondary windings.

Abstract: In a gate pulse generator for a thyristor converter of the type in which in order to fire thyristors of the thyristor converter in which each arm is comprised of a plurality of series-connected thyristors, the gate pulses are generated in response to the gate command signal and the thyristor forward voltage signal and are converted into the light signals which in turn are transmitted to the thyristor converter, whether or not the forward voltage signal exists when the gate command signal is generated is detected and when the forward voltage signal is generated prior to the generation of the gate command signal, the pulse duration is narrowed to a minimum required for firing the thyristor.

Abstract: The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level.

Abstract: A high voltage power supply current regulator includes at least one high voltage rectifier diode having a plurality of pn junctions, said diode being adapted to be connected between a high voltage power supply whose current is to be regulated and a load such that the diode is reverse biased. A control circuit, operating at a voltage which is relatively low compared with the power supply voltage, controls the reverse current through the diode to the load. The reverse current constitutes the load current. The control circuit includes a light source for illuminating the pn junctions of the diode with a predetermined flux of photons, the reverse current through the diode being a function of the photon flux on the diode junctions.

Abstract: A low voltage shutdown circuit for a PWM power supply includes a voltage divider supplying bias for a transistor having a load resistor that is part of an integrating network. The capacitor in the integrating network is coupled to a voltage sensitive switch (Diac) which feeds an LED detector in a photo optic coupler. Under normal conditions, the transistor is in saturation and the capacitor is discharged. The transistor comes out of saturation when the voltage level across the divider drops to a predetermined level and the capacitor charges to the trigger voltage of the Diac, which fires the LED in the photo optic coupler for developing a shut-off signal.

Abstract: An optical pulse receiving device converts an optical pulse signal into an electric signal, maintains a maximum value of the electric signal and sets a threshold voltage at one-half the maintained signal using a resistor divider. A comparison circuit compares the converted electrical signal with the threshold voltage and emits an output pulse on the basis of the comparison of the two signals. The output pulse is a square pulse with accurate timing.

Abstract: A plurality of controlled avalanche semiconductor elements, are connected in series and are irradiated with a controllable quantity of light to form circuits which in principle can switch an unlimited high voltage or can control such a voltage. Dissipating auxiliary means to obtain a uniform voltage distribution cross the circuit are not required. As a light source, light-emitting diodes can be used so that the elements can be controlled at a low-voltage level and with DC separation the circuit can be used in high-voltage amplifiers, high-voltage regulators or high-voltage stabilizers, deflection voltage generators, high-voltage switches in X-ray apparatus, lasers, ignition systems in combustion engines etc.

Abstract: An electronic switch with CSE wiring, especially a triac, has a load connected in series therewith to an a-c voltage network. A rectifier bridge circuit has its a-c terminals connected into the driving circuit of the electronic switch. The d-c terminals of the bridge circuit are connected to a light-emitting diode poled in the conduction direction. Since the firing current for the switch is periodically repeated, the light-emitting diode indicates the switching state of the triac since the brief pauses without current of the LED are not perceived by the human eye.

Abstract: A gyrator is comprised of a first voltage-current converter for converting the first voltage applied to a first terminal into electric current, a first light-emitting diode for converting the output current of the first voltage-current converter into a corresponding photosignal, a first phototransistor optically connected to the first light-emitting diode, the transistor converting the photosignal from the first light-emitting diode into a corresponding current, the transistor further supplying the converted current to a load capacitor connected to a second terminal, a second voltage-current converter for converting voltage, which is caused at the second terminal by the load capacitor, into a corresponding electric current, second light-emitting diode for converting the output current of the second voltage-current converter into a corresponding photosignal, second phototransistor optically connected to the second light-emitting diode, and for converting the photosignal from the second light-emitting diode int

Abstract: A circuit is described for automatically controlling an input current to a current translating device having an output current functionally related to the input current. A sensing circuit detects the output current of the device and produces a control signal representative of the output current. The control signal is coupled to a control circuit that varies the input current to the device. In the preferred embodiment of the invention, the dynamic range of the sensing circuit is increased by coupling a constant current generator to its input.

Abstract: An optically-triggered converter directly changes the frequency of an incoming voltage waveform to half frequency thereby causing an induction motor, driving a ventilation fan or the like, to operate at half speed. At this lower speed, the induction motor consumes significantly less power. A center-tapped power transformer is used to lower the magnitude of the incoming voltage waveform and a number of optically-triggered thyristor switches are connected between the transformer secondary and the induction motor. The novel trigger circuit includes a synchronous motor connected to receive the input voltage waveforms so that a cylinder attached thereto is rotated in synchronism with the input voltage waveforms. The optically-triggered thyristors are circumferentially positioned about the rotating cylinder and are triggered by a light pulse emerging through an aperture in the cylinder sidewall.

Abstract: A computer network is disclosed in which a plurality of computer work stations are interconnected for interstation communications by a single electrically continuous bi-directional bus. Each computer work station includes a data processing device and a transceiver. The transceiver includes a receiver section for receiving signals transmitted over the bus and a transmitter section for transmitting signals onto the bus. The receiver section is coupled to the input of the data processing device by a first optical isolator and the transmitter section is coupled to the output of the data processing device by a second optical isolator. The data processing device and the first optical isolator are powered by a first power supply which is connected and grounded to the AC mains while the transceiver and second optical isolator are powered by a second power supply which is connected to the neutral conductor on the bus and is floating.

Abstract: An inrush current limiter includes at least a two-terminal circuit in series with a power load having a high gain high current Darlington transistor, a driver transistor for the high gain high current Darlington transistor, a current sensing resistor, a base-drive resistor, and a diode bridge interfaced for providing a peak-current-limiting function by proportional adjustment of the voltage to the power load as a function of current.

Abstract: A solid-state dimmer control circuit using opto-isolators, whereby the effective power to be supplied to a load is selectively varied. The opto-isolators couple a variable pulse switching circuit to a full-wave switching circuit which includes back-to-back silicon-controlled rectifiers. The variable pulse switching circuit is connected to means for generating a selectively variable control signal that is proportional to the power to be supplied to the load. A single a.c. power source is provided both switching circuits.

Abstract: A full-charge indicator for battery chargers, includes a transistor which is in a conductive state as long as charging current to the battery is not less than a level which indicates that the battery did not reach full charge. When the battery reaches full charge, a voltage drop in a resistor in the charging current path is not sufficient to maintain the transistor in a conducting state, and therefore it is switched off. When this occurs an LED is turned on, to indicate a full charge state of the battery. A photocoupler together with a photocoupler transistor are included. When the transistor is off, the photocoupler activates the photocoupler transistor to shunt out a resistor, thereby reducing the charging current to the battery to a float charging current and prevent the battery from being overcharged and damaged.

Abstract: A power supply suitable for energizing an isolation amplifier requiring its input section to be isolated electrically from its output section. The power supply consists of a primary circuit, which, when energized by an electrical supply, converts the electrical energy to infrared radiation, and a secondary circuit which includes a solar cell or cells arranged to receive the infrared radiation. Electrical energy is generated by the solar cell or cells when irradiated. The primary circuit of the power supply includes a plurality of infrared emitting diodes which are energized electrically to provide infrared radiation. The current produced by the solar cell or cells in response to the radiation is applied to a regulating circuit.

Abstract: A battery charger has a control circuit portion and a power circuit portion with common terminals to connect to a battery desired to be recharged, the power circuit includes a transformer and rectifier to deliver at least partially rectified A-C current to the battery, and an A-C power connection through which A-C power is supplied to the power circuit with the control circuit having a solid state switch to selectively connect the A-C power to the power circuit portion. The control circuit portion of the charger has a D-C disconnect feature which senses the interruption in the electrical circuit between the charger's terminals and the battery, said disconnect feature causing the operation of the A-C power switching device to disconnect the A-C power from the power circuit after the terminals have been disconnected.

Abstract: A free-running blocking oscillator-type converter for producing a controlled output signal. The converter is provided with a primary winding of a transformer, a switching transistor, and a resistor which are connected in series with one another between first and second input terminals of the converter. The transformer is further provided with a feedback winding which is coupled to the base terminal of the switching transistor. In some embodiments, optoelectronic coupling devices are used in a sensor arrangement for providing a control signal responsive to variations in the magnitude of the output signal of the converter. In other embodiments, such variations in the output signal of the converter are sensed by a transformer winding. Circuitry is disclosed for applying the sensor control signal selectably to the base and emitter terminals of the switching transistor.

Abstract: Circuits for providing a variable-amplitude D.C. analog control signal to a load, responsive to the time duration of a periodic, variable-pulse-width input signal, while providing isolation between the input signal circuit and the load circuit. Embodiments utilizing either a fly-back transformer or an optoelectronics isolator, are disclosed.

Abstract: In a remote control system which is operated by way of a light wave guides, a monitoring device is provided for a remotely controllable load, the monitoring device measuring the current through the load and deriving values therefrom for the proper and the improper operating state of the load. All switches participating in the drive and monitoring functions with respect to the load are incorporated in a check concerning the operability of the monitor and of the load, the check being carried out during operation of the load.

Abstract: Light-activated power FETs (18, 20, 80, 82) are utilized as switching elements in DC-to-DC converters. The FETs are characterized by high speed and low losses. As a result, the converters are capable of providing very low DC voltages in an efficient low-cost way.

Abstract: A circuit for controlling power delivery to different AC inductive loads, which loads create different respective lag angles between applied voltage and delivered current up to a known maximum lag angle. Included is a switching circuit, typically including silicon-controlled rectifiers, connected to the load. The switching circuit is trigger-pulse-switched into conduction, and thereafter maintained in conduction so long as current through the load exceeds a certain minimum value. Additionally, a trigger-pulse generator connected to the switching circuit operates in two modes. In one mode, the conduction angle is less than a predetermined maximum width which is no less than the maximum lag angle. In this mode, a pulse is generated whose width is essentially equal to the conduction angle. In the other mode, the conduction angle is no less than the maximum width, and the generated pulse has a fixed width substantially equaling the maximum width.

Abstract: A half-wave and a full-wave rectifier using transistors as rectifying elements have independently controlled multiple output voltages obtained from a single power supply. The transistor used as a rectifying element has its turn-on controlled thus allowing voltage control by phase control action.

Abstract: A phase control device for use in a phase control circuit, which forms a comparison signal synchronous with an a.c. power source, then compares this comparison signal directly with a preset phase control angle signal, and controls a phase control element provided in the a.c. phase control circuit by the compared output.

Abstract: A phase fired controller is provided for eliminating large shifts in the firing angle due to line voltage variations. Another advantage of the controller is that variations resulting from parts tolerances are reduced substantially. This is accomplished by controlling the output of a capacitor that supplies a voltage to a comparator. The system has particular utility when used as a dimmer controller of an electrostatic copier.

Abstract: A thyristor power controller for rapidly varying the current delivered to a load and including: a clock circuit for developing a clock pulse for each zero crossing of an AC source, an analog phase circuit responsive to an adjustment current and operative to produce a firing signal for each clock pulse, a first thyristor acting on a positive half cycle of an AC source, a second thyristor acting on a negative half cycle of an AC source, a first thyristor control circuit enabling and disabling the first thyristor, a second thyristor control circuit enabling and disabling the second thyristor, and a thyristor selector operative to route the firing signal to the first or second control circuit.

Abstract: A power control circuit has a thyristor bridge interposed between a.c. buses connected to an a.c. power supply and a load. The firing circuit for the thyristors of the bridge includes a light actuated controlled rectifier for generating firing pulses. Two series connected resistor-capacitor pairs are connected in series across the a.c. buses. Taps intermediate the resistors and capacitors provide an energizing anode voltage to the controlled rectifier reduced with respect to the a.c. voltage in the buses. The voltage reducing and capacitive properties of the pairs render operation of the controlled rectifier immune to transient voltage spikes in the a.c. buses.