Abstract: An AC voltage regulator which detects the instantaneous supply voltage in a phase shifter and compares it with the reference voltage by a comparator circuit so that in response to the output signals from the comparator, the firing angle of the thyristors connected to a supply voltage circuit may be controlled in order to maintain constant the effective load current.

Abstract: In a monitor for determining the real electrical power being delivered by a 3-phase source to a load, each phase voltage and a voltage which is proportional to and in phase with the corresponding line current are coupled to separate balanced detectors Each detector provides a DC voltage which is proportional to the real power being delivered by its corresponding phase The DC voltages from the balanced detectors are connected in series and the resulting sum voltage is coupled to a plurality of voltage comparators Each voltage comparator provides a signal when the sum voltage exceeds a predetermined magnitude and each of the voltage comparators is set to respond to a different sum voltage magnitude Since the sum voltage is proportional to the real power being delivered by the source, within the range of voltage magnitudes set, the output signals of the voltage comparators provide a measure of the power being delivered by the 3-phase source A binary output means, such as a relay, is controlled by each comparator

Abstract: A device for electrically heating a semiconductor rod which is simultaneously growing due to a depositing process from the gas phase employs a heating current source for supplying an alternating voltage and an electronic switch which is operated by a time wise variable auxiliary voltage for controlling the application of heating current supplied by the heating current source to the semiconductor rod. A second circuit is coupled to the aforementioned circuit to rectify the applied voltage and pass the rectification product to a four-pole smoothing filter circuit. The differential voltage at the output of the four-pole circuit, with respect to a reference voltage, serves to control a generator for generating the auxiliary voltage in such a way that the auxiliary voltage is applied earlier in response to larger values of difference voltage.

Abstract: A method of and an apparatus for controlling the frequency of a polyphase alternating current supply applied to a polyphase load. SCR''s or triacs are connected in matrices between each supply phase and each end of each load phase and selected sets thereof are made available for triggering in a predetermined stepping sequence. The current flow in the supply phases is monitored and when current zeros are detected in the supply phases the then available set of SCR''s or triacs are triggered. If desired, current zeros can be induced in the supply phases. The frequency applied to the load is controllable by varying the rate at which the sets of SCR''s or triacs are made available for triggering. The effective voltage applied to the load is also controllable by varying the time period between the detection of current zeros and the triggering of the sets of SCR''s or triacs.

Abstract: This invention comprises a circuit and apparatus for sensing the input voltage to a device and for boosting the input voltage when it falls below a predetermined acceptable level so that the voltage supplied to a device is relatively constant. A sensing circuit acts to switch in the boost winding of an autotransformer when the input voltage is below the predetermined level. A second sensing circuit and apparatus is provided which senses a second input voltage level, lower than the first, and which disconnects the load device when the input voltage is below the second level.

Abstract: The repeating chain of pulses of a GeMSAEC analytical photometer is referenced to a constant amplitude water blank pulse that is sampled with each revolution of the rotor. A feedback circuit samples the amplitude of the water blank cuvet signal by means of a fast-acting solid state switch. It assures that the water blank signal amplitude remains constant by controlling the photomultiplier tube high voltage supply following comparison of the water blank transmission signal with a very well regulated reference voltage. Thus, in the event of photomultiplier gain change or power supply drift during operation, automatic restoration of the photometer data transmission signals to their correct values will occur.

Abstract: Various forms of a.c./d.c. 4-quadrant thyristor controllers, based on the circulating-current principle, are described. The relative advantages and disadvantages of circulating-current schemes and logic-interlocked schemes are discussed and a new current or voltage controller with a linear transfer characteristic is described. It is shown how such a scheme can be operated on the circulating-current principle with the circulating current effectively zero.

Abstract: A circuit for converting an input voltage of variable frequency into an output voltage having a predetermined, lower frequency by means of a controlled static frequency converter which is operated as a direct link inverter. The output voltage of the frequency converter is multiplied in a first multiplier circuit by a sine voltage and in a parallel connected second multiplier circuit by a cosine voltage. The respective a-c components in each parallel circuit are filtered out in succeeding smoothing members. The remaining d-c voltage components are then each added in a summing point to preset reference values. The sum voltages are each fed to a voltage regulator, which is followed by a third and fourth multiplier, respectively. In the third and fourth multiplier the output of the voltage regulator is multiplied by the identical sine and cosine voltages. The last-mentioned multipliers are then connected to a common summing point which feeds a control voltage to the control unit of the frequency converter.

Abstract: The device is used in a camera having film transport means intermittently advancing a film and a picture taking optical system. A stationary element, having a light transmission factor variable in accordance with the magnitude of an applied voltage, is interposed in the path of light passing through the optical system to the film, and a light beam splitter is positioned between the stationary element and the film to split the light into a beam directed to the film and another beam incident upon a photo-electric converter. A voltage controller connects the converter to the stationary element to control the light transmission factor thereof in accordance with light incident upon the converter. An electrical signal generator, such as a pulse generator, is connected to the film transport means and generates output pulses intermittently in accordance with stepwise advancing of the film by the transport means. The output of the pulse generator is connected to the voltage controller to control the operating time of the voltage controller in accordance with operation of the film transport means to interrupt operation of the controller, to block light transmission through the stationary element, during each stepwise advance of the film by the film transport means. Thereby, the stationary element functions simultaneously as an automatic exposure control and as a shutter for the camera.

Abstract: A simple voltage to time proportional controller, for use in temperature control circuits is described. The input is the output of a null detector. The output is a relay which can be used to control either a valve or a heater.