Showing papers on "Current divider published in 1972"

Frequency modulator-variable frequency generator

Abstract: A frequency modulator/variable frequency source employs an electronically programmable divider in the feedback path of a phase locked loop. The phase locked loop is stabilized by the output of a fixed frequency oscillator. The effective divider modulus is directly determined by a variable duty cycle signal which alternately switches the divider between two characteristic count capacities with relative dwell periods determined by a modulating potential.

Low Temperature Voltage Divider and Null Detector

Abstract: This paper describes a low temperature voltage divider and null detector which are designed to accurately bring the low level voltage of the Josephson steps to the 1 V level. The divider uses the series‐parallel interchange of resistors. Preliminary tests indicate that the resistors are stable to within one part in 107 and that the ratio is accurate to within one part in 106. The null detector utilizes a superconducting quantum interference magnetometer and is limited only by the Johnson noise in the cooled resistors.

Precision Capacitive Voltage Divider for Impulse Voltagge Measurements

Abstract: This paper describes a precision capacitive voltage divider for impulse voltage measurements. The main feature of the new divider is a compressed-gas capacitor in the high-voltage arm. The divider is insensitive to environmental influences, possesses outstanding high-frequency properties, and causes little loading of the high-voltage circuit. Its excellent linearity and stable ratio permit meaningful high-voltage pulse measurements in the megavolt range.

A Reliable Multimegavolt Voltage Divider

Abstract: A two stage, dc coupled, linear resistive voltage divider having a risetime of 1.5 nsec has been used to measure voltage pulses up to 1.8 MV on a pulsed electron accelerator. The monitor has proved to be stable, reliable, and has required little maintenance.

Circuit for converting dc voltage into three-phase voltage

Abstract: A circuit for converting a DC voltage or a three-phase voltage of variable or constant frequency into a three-phase voltage of a constant other frequency utilizes an intermediate circuit frequency converter. The converter comprises two three-phase thyristor inverters, connected in parallel at the input side. The three-phase outputs of the one three-phase thyristor inverters are connected together via voltage divider chokes. The taps of the voltage divider chokes provide the three outputs of the converter.

Electric meter with logarithmically indicating digital reader

Abstract: A variable voltage to be logarithmically indicated is fed to an input of an operational amplifier acting as a constant-current source in charging or discharging a capacitor at a constant rate determined by the magnitude of that voltage. The time required for the capacitor to charge or discharge from a reference potential to a potential equal or proportional to the variable voltage (or vice versa) is measured by a digital counter to which the output of a constant-frequency pulse generator is supplied, during the charging or discharging interval, through a binary frequency divider with a multiplicity of cascaded binary stages which are progressively cut in or out by a programmer responding to a predetermined number of pulses in the divider output, thereby modifying the pulse rate in the divider output in discrete steps by a factor of 2. Intermediate steps, designed to provide a closer approach to a logarithmic function, involve the alternate insertion of two final stages of stepdown ratio 5:1 and 7:1 in cascade with the binary stages to establish a pulse-rate modification by a factor of approximately square root 2.

Retriggerable one-shot multivibrator

Abstract: A retriggerable one-shot multivibrator is realized by employing a plurality of inverting logic gates, a digital divider and a clock circuit. A first logic gate is used to control the supply of clock pulses to the divider. A second logic gate responds to the divider output to yield the desired multivibrator output and to control the first logic gate. The one-shot multivibrator is triggered by clearing the divider.

Current transformer connection control

Abstract: An apparatus for detecting specific conditions in a current transformer during the establishment of a short circuit current and anticipating saturation to prevent the connection of the transformer output to a utilization device. The apparatus include a voltage divider connected to the secondary winding and an integrater connected to integrate a portion of the voltage developed across the divider. The result of the integration is monitored as to direction and magnitude and an output signal is generated which is indicative of both direction and whether or not the magnitude has exceeded a predetermined threshold. This value is used as being representative of the generation of flux in the magnetic circuit. Simultaneously, the sign of the derivative of the current is determined. The signals thus generated are coupled to a circuit which performs the logical decision S A.B + A.C. A signal resulting from this decision inhibits connection of the transformer to the utilization device.

Half wave voltage divider

Abstract: An electrical circuit is provided in which a bank of capacitors is controllably charged in series and then discharged in parallel through the interaction of a voltage divider, a silicon controlled rectifier, and diode circuit elements to transform a sinusoidal line voltage into a half-wave pulse. The magnitude of the pulse is a function of the RMS line voltage input and the number of capacitors in the bank. This function may be expressed as 1/(k).V/n where V is the RMS line voltage input, n is the number of capacitors in the banks and k is the transformation and round-off error constant.

Network having a resistance the temperature coefficient of which is variable at will

Abstract: A temperature compensation network having a resistance that exhibits a temperature coefficient that is adjustable substantially independently of the voltage applied to the network. The network includes a resistive voltage divider connected in parallel with the emitter-collector path of a transistor. The base of the transistor is connected to a tapping on the voltage divider. A zener diode having a zero temperature coefficient relative to the transistor temperature coefficient is connected to the voltage divider, whereby the network exhibits a net negative temperature coefficient of resistance.

Remote sensing circuit

Abstract: An electronic sensing circuit for use with a balanced two-wire load including a pair of voltage divider networks connected thereto, respectively. The midpoint nodes of the voltage divider network have substantially equal voltage levels in one state of said load and have a voltage differential measurable therebetween in another state of said load. A voltage differential detector means such as a capacitor or differential amplifier is used to measure the voltage differential between the midpoint nodes.

Low output impedance voltage divider network

Abstract: A low output impedance precision dynamic voltage divider network having low power dissipation and particularly suited for fabrication on a monolithic integrated circuit chip.

Trigger comparator circuit

Abstract: A trigger comparator circuit having an operational amplifier which compares a reference voltage with a sample of a source voltage developed across a second portion of a first voltage divider. When the source voltage increases beyond a predetermined level a corresponding signal is generated at the output terminal of the operational amplifier which begins to drive a transistor switch into conduction. The transistor switch in turn channels current through a first portion of the first voltage divider so as to increase the voltage level appearing at the second portion of the first voltage divider until the transistor switch is driven into saturation.

Technique for extending the frequency range of digital dividers

Abstract: A technique for extending the frequency range of a presettable digital divider. The conventional digital divider consists of several counter stages with the count of each stage compared to a preselected number. When the counts for all stages are equal to the preselected numbers, an output pulse is generated and all stages are reset. For high input frequencies, the least significant stage of the divider has to be reset in a very short time. This limits the frequency that can be handled by the conventional digital divider. This invention provides a technique in which the second least significant and higher stages are reset and the least significant stage is permitted to free-run. Hence, the time in which the reset operation can be performed is increased thereby extending the frequency range of the divider.

A coaxial capacitive voltage divider for oscilloscopic recording of nanosecond high voltage pulses

Abstract: A coaxial capacitance voltage divider with a ratio of 110 and a rise time much less than 2.5 ns was developed for use with a transmission line pulse generator capable of producing 100 kV rectangular pulses of 2 mu s duration. The low voltage arm of the divider is a 3 cm long tube of titania (TiO2) turned out from a cylindrical compact. The compact was made by first pressing titania powder using a suitable binder and then sintering at controlled temperatures. The tube was slipped over the terminating end of the pulse-forming cable to form the divider with the cable capacitance.

Frequency divider circuit

Abstract: A clockless FARMOST toggle flip-flop circuit is combined with a pair of ratioed inverters, a clock supply, and a DC power supply to form a simple, low-power frequency divider.

Light modulated voltage divider control

Abstract: A light modulated voltage divider control for tuning voltage responsive television tuners utilizes a separate polarized light filter means corresponding to each channel to be tuned. The polarity orientation of the separate filtering means are individually adjustable. All channel UHF, VHF and VHF-UHF combinations are provided.

Adjustable stable power supply for continuous wave magnetron

Abstract: A power supply circuit for a continuous wave magnetron provides adjustable stable power levels. A first direct voltage source is connected across the magnetron and a second direct voltage source from a common alternating voltage source is connected across the magnetron coil in series with a direct current amplifier. Current feedback to the input of the amplifier is derived from the magnetron by an adjustable voltage divider connection to the first voltage source. Another portion of the voltage divider provides a third direct voltage connection between the second source and amplifier input, the amplifier input current being the sum of current from the third source and adjustable current from the magnetron.