Showing papers on "RLC circuit published in 1973"

A study of locking phenomena in oscillators

Abstract: Impression of an external signal upon an oscillator of similar fundamental frequency affects both the instantaneous amplitude and instantaneous frequency. Using the assumption that time constants in the oscillator circuit are small compared to the length of one beat cycle, a differential equation is derived which gives the oscillator phase as a function of time. With the aid of this equation, the transient process of "pull-in" as well as the production of a distorted beat note are described in detail. It is shown that the same equation serves to describe the motion of a pendulum suspended in a viscous fluid inside a rotating container. The whole range of locking phenomena is illustrated with the aid of this simple mechanical model.

Single Coil Series Resonant Circuit for Pulsed Nuclear Resonance

Abstract: This paper presents a description of and design optimization criteria for a series resonant single coil system suitable for use in pulsed nuclear magnetic or quadrupolar resonance. The design is adaptable to the frequency range 1–100 MHz, and permits both efficient use of transmitter power and signal reception with a high signal‐to‐noise ratio. An example of the design of a system to operate at 10 MHz is worked out and compared against the ideal case. An active damping circuit to speed the recovery following an rf pulse is also discussed.

Induction heat cooking apparatus

Abstract: There is disclosed apparatus for heating a cooking utensil by magnetic induction from the work coil in a series resonant circuit driven by an oscillator operating at and tracking with the resonant frequency of the series resonant circuit, the apparatus being provided with structural, operating, and safety features, including a) protection against high Q loads, and b) closed loop heat and coil current regulation.

Frequency controlled inverter

Abstract: In a regulated dc to dc converter, a ferroresonant regulator is combined with a push-pull inverter on the same transformer, and a feedback circuit controls the frequency of the inverter in response to the rectified output of the regulator. A control winding on the inverter transformer is tightly coupled to the base drive windings that supply drive to the inverter transistors and loosely coupled to the primary winding that is driven by the transistors. The control winding is short circuited each half cycle at a time determined by the feedback circuit to reflect a low impedance into the base drive windings and a higher inductive impedance into the primary winding. The higher inductive impedance in combination with a capacitor in parallel with the primary winding forms a resonant circuit which insures efficient commutation of the inverter transistors and the control winding short circuiting device.

Centrifugal separator with sensing means

Abstract: A first unit rotating with the centrifugal rotor forms an electric resonance circuit having at least one variable oscillation property; and a sensing member rotating with the rotor is arranged to sense a displacement of an interface formed between two media undergoing centrifugal separation in the rotor, the sensing member acting to change the variable oscillation property of the resonance circuit in response to a sensed displacement. A second unit separate from the rotor comprises means for inductively transferring a signal to the resonance circuit and also includes means for sensing a change of the load by the resonance circuit on the signal transferring means in response to a change of the variable oscillation property of the resonance circuit.

Local oscillation circuit for reducing oscillation voltage variations between high and low frequency bands

Abstract: The proposed local oscillation circuit comprises a resonance circuit including a variable capacitance diode to change the resonance frequency and tuning coils for low and high frequency bands, an oscillating transistor connected with the resonance circuit, changeover means for switching the tuning coils between the low and the high frequency bands, biasing means for providing a bias voltage for the oscillating transistor, and means for changing over a collector current of the transistor by changing the bias voltage applied by the biasing means to the transistor, in response to the operation of the tuning coil change-over means. The local oscillation circuit is well adapted to be used in a tuner of a receiver which receives a wide range of frequencies, e.g. a VHF television tuner.

Variable time constant circuit for use in an electronic musical instrument

Abstract: In the variable time constant circuit of this invention, at least either or both of the resistor and capacitor included in the time constant circuit and acting as the elements for determining the time constant thereof are split into a plurality of units and a normally open or closed switching element selectively closed or opened concurrently with performance of the instrument is connected in parallel with the split resistor or in series with the split capacitor. Such a variable time constant circuit can be triggered by encoded pattern pulses and is used, for example, as an envelope control circuit, a tone coloring circuit, or the oscillating frequency or duration determining circuit portion of a percussion sound oscillator included in each rhythm sound source of the automatic rhythm instrument.

Analysis of High Frequency Inverter Circuit

Abstract: A bridge inverter circuit with tuned load is analyzed. A number of nomograms are presented and their use in the choice of circuit components is discussed.

Voltage controlled oscillator

Abstract: A voltage controlled oscillator comprising an amplifier, a series resonance circuit, formed of a coil, a capacitor and a resistor, to which the output of said amplifier is supplied, a composite circuit for taking the vectorial sum and difference between a voltage across said resistor and a voltage across said coil or capacitor, a circuit for vectorially adding the sum signal and the difference signal at rates responsive to an external control voltage, and means to positively feedback the output of the adder circuit to the input side of said amplifier, the phase of said output of said adder circuit being changed in response to said external control voltage, to make the oscillation frequency of said oscillator variable.

Tuner with integral input filter

Abstract: A television tuner has a UHF section comprising a stamped metal subchassis having a plurality of resonant circuit elements whose electrical characteristics are adjustable by deforming portions thereof and a thick film integrated circuit VHF section. A metal housing supports the stamped metal subchassis and thick film integrated circuit and a metal shield encloses the stamped chassis and integrated circuit. The thick film integrated circuit includes an RF amplifier, mixer, local oscillatr, and an input filter network which attenuates signals between 88 and 108 MHz as well as those at or near the IF frequency of 45.75 MHz. The input filter network can be aligned while coupled to the RF amplifier input network.

High speed light beam modulator

Abstract: A high speed light beam modulator includes an electro-optic modulator which is connected in series with an inductor to form a series resonant circuit. Switching means selectively allows current to flow in the inductor for a predetermined period. The switching means then interrupts the flow of current, causing oscillations in the series resonant circuit. The oscillations are damped after the first half cycle of voltage oscillation appearing across the electro-optic modulator.

Remote control circuit and apparatus for exploding explosives

Abstract: A remote control circuit and apparatus for exploding explosives. Electric power generated at a resonance circuit when it is tuned to a control electromagnetic field is used to charge an ignition condenser. Provision is made for a control circuit including a controlled rectifier called a triac. The control circuit is adapted to generate a starting pulse at an instant when the control electromagnetic field is extinguished. The starting pulse serves to make the controlled rectifier conductive and hence discharge the ignition condenser through a detonator, thereby initiating it and exploding blasting explosives used to break rock and other solid material.

Quenched-Domain Mode Oscillation in Waveguide Circuits

Abstract: An experimental study of pulsed transferred-electron oscillators operating in waveguide circuits is reported. Quenched-domain mode operation is shown to be present for short (less than 20-/spl mu/m) supercritically doped GaAs samples operating at X-band frequencies (8.2-12.4 GHz) and for bias-voltage values up to six times threshold value. Analysis of the waveguide circuit shows that the chip sees a parallel resonant circuit, and theoretical computations with a sinusoidal voltage waveform are shown to be reasonably accurate. The load admittance presented to the chip is experimentally evaluated.

Low noise VHF oscillator with circuit matching transistors

Abstract: A VHF oscillator circuit is disclosed providing a higher stable gain than achieved with prior art designs In particular, there is disclosed first and second transistors, a first resonant circuit coupled to each of the collectors of the first and second transistors, and means typically taking the form of a transformer for coupling energy from the first resonant circuit in a manner that signals of substantially equal amplitude but opposite phase are applied respectively to the bases of the first and second transistors Further, bypass means typically taking the form of a capacitor is connected to the emitter of the second transistor In addition, an antiresonant circuit comprising a crystal unit is connected to the emitter of the first transistor and a suitable diode limiting circuit is provided to prevent saturation of the first and second transistors

Horizontal linearity correction circuit

Abstract: A cathode ray tube deflection circuit having a flyback transformer coupled to a potential source and via a parallel coupled horizontal output stage and a horizontal deflection yoke to a potential reference level with a damper stage coupled to the junction of the transformer means, output stage, and deflection yoke includes a linearity correction circuit wherein a winding of the transformer means coupled to a potential reference level is also coupled to a series connected switching means and series resonant circuit connected to the potential reference level and to the damper stages whereby the rate of change of current flow through a deflection yoke is altered to enhance linearity of the trace period of a cathode ray tube.

Vlf frequency diversity trailing wire transmitting antenna

Abstract: Aircraft VLF/LF frequency diversity transmitting antenna. The antenna comprises a long trailing wire of length approximately equal to one-half the wavelength of the lower of two operating frequencies. A resonant circuit is connected to the wire at a distance from the aircraft and transmitter approximately equal to one-half the wavelength of the higher of the two frequencies. The resonant circuit is tuned to one of the two frequencies to effectively connect or disconnect the portion of the wire between the resonant circuit and the far end of the wire in accordance with which of the two frequencies is exciting the trailing wire, whereby the antenna reactance is changed to facilitate retuning.

A receiver circuit including a crystal resonator for nuclear magnetic resonance signals of two different frequencies

Abstract: A receiver circuit for a nuclear magnetic resonance analyser includes a resonance circuit and an amplifier circuit. The resonance circuit includes a receiving coil for detecting nuclear magnetic resonance signals of two different frequencies and a crystal resonator connected in series with the receiving coil. The crystal resonator being chosen so that it is substantially inductive at the lower of the two frequencies and is substantially capacitive at the higher of the two frequencies. The output impedance of the resonance circuit is matched to the input impedance of an amplifier circuit to which it is attached at the two different frequencies. By use of this circuit signals of the two different frequencies may be amplified by a single amplifier.

Analysis of a Forced Commutation Circuit for Design of a Class or Thyristor Inverters

Abstract: The literature contains a variety of inverter circuits with forced commutation. In general, the auxiliary circuit for switching off the load current carrying thyristors is composed of a number of energy storage components and semiconductor switches which are affected by losses. These circuits demonstrate specific advantages under certain conditions. The analysis of a forced commutated inverter with a series LC-resonant circuit is presented in this article. The peak capacitor voltage depends on the quality of the resonant circuit and the ratio of the peak capacitor current vs. the maximum load current. This can cause high stresses on all the components of the inverter circuit. The set of equations for the circuit is established and used for the computation of results. The peaks of stored energy and the losses in the commutation circuit are calculated and given in a normalized form. Design parameters in normalized form are derived therefrom and presented in this article.

Amplitude corrector for the chrominance component of a colour television signal

Abstract: An amplitude corrector for the chrominance component modulated in phase and amplitude of a complex colour television video signal in which the phase is maintained constant and in which the separation of luminace and chrominance spectra is not necessary. A series resonant circuit is used whose inductance and capacitance are associated with a pi -lowpass filter whose input terminal is connected to a variable resistor controlled by an auxiliary amplifier.

Crystal puller - with automatic flash-over protection for induction heater

Abstract: The conventional induction heating coil with tank capacitor forming the resonant circuit is fed by a RF generator. Coupled to this is the protection circuit which is based on rectified output from the tapping point of a capacitative potential divider, connected to the tank circuit being fed to a protection stage including a bi-stable Kipp relay whose response is adjustable by a variable resistor in the emitter circuit of the transistors. The Kipp is followed by a switching stage that cuts off the RF supply and the drive to the puller in the event of a voltage breakdown. Automatic prevention of damage to equipment or prod. semiconductor bar is effected.

Device for preventing oscillation of LRC circuit

Abstract: A device for preventing the oscillation of an LRC circuit of an electronic shutter control circuit includes a control circuit and a converter. A low-pass filter is interconnected between a terminal of the control circuit, from which is derived a voltage for setting an exposure, and a terminal of the LRC circuit, thereby effecting the positive feedback of the oscillation signal of the LRC circuit. The low-pass filter includes resistors and a diode connected in series and a capacitor, one terminal of which is connected to the juncture of the resistors.

A driver circuit for actuating print wire solenoids

Abstract: A driver circuit for energizing solenoids to actuate print wires wherein the solenoid operation is such as to rapidly move the print wire into impact direction and permit rapid return thereof. The drive circuit provides for an external determination of the solenoid drive time. A transistor having a current limiting resistor coupled thereto drives the solenoid. Current amplification means is coupled to the imput of the transistor and its input, in turn is controlled by a voltage regulating semiconductor device for maintaining constant current through the solenoid. Capacitance means coupled to the inductor through diode means provides a discharge circuit for the solenoid. A capacitor cooperates with the solenoid inductance to form a resonant circuit enabling the current through the solenoid to decrease in a short time period and prevent generation of high voltages during reverse conduction of the inductance. Control circuit means preventing energization of the solenoids during cutoff of the solenoid power source.

Series--parallel RLC synthesis of bicubic impedance

Abstract: Even after minimisation, the Bott–Duffin transformerless synthesis requires the solution of a higher-order equation to obtain a certain parameter occurring in the augmentation factor. The present RLC synthesis for bicubic impedances merely needs, after minimisation, the solution of a 1st-order equation to accomplish a generalised continued-fraction realisation.

Transistor oscillator with diode in feedback circuit providing amplitude stabilization

Abstract: A voltage-dependent capacitor tuned oscillator employs a diode as a coupling element between an amplifying device and a resonant circuit to provide a feedback signal to the amplifying device required to sustain oscillations. The diode further provides charging current for a capacitor in the resonant circuit when a first polarity portion of the oscillations increase above a predetermined level. The charge on the capacitor decreases the feedback level, thus stabilizing the level of oscillations in the resonant circuit for each frequency to which the oscillator is tuned.

Response analyzing device

Abstract: A response analyzing device comprises a discriminating device and a plurality of answering devices connected in parallel to a plurality of lines extending from the discriminating device. Each of the answering devices are provided with resonance circuits having mutually different resonance frequencies and a selective switch for connecting the resonance circuits with these lines. The discriminating device is provided with a sweep oscillator for impressing outputs to these lines and has a variable range which permits the sweeping of the entire range of the resonance frequencies and circuitry for detecting the variation in impedance due to the resonance phenomenon created in the resonance circuit.

Gated filter circuit

Abstract: The system is of the type that comprises a Gunn oscillator, transmitting and receiving antennas, and a mixer circuit. If there is intruder motion the doppler signal from the mixer circuit passes by way of a filter circuit and integrator to an output alarm circuit. In one embodiment the filter circuit is a notch filter that exhibits infinite attenuation above a predetermined frequency, such as 120 hertz, while passing lower intruder frequency signals. The system is also provided with novel supervisory alarm circuitry.