Relaxation oscillator

About: Relaxation oscillator is a research topic. Over the lifetime, 1952 publications have been published within this topic receiving 22326 citations.

Circuit arrangement for generating radio frequencies

Abstract: The invention provides a general purpose RF oscillator which may have any of many uses, depending upon bias and voltage levels which may be used. An LC circuit is repeatedly triggered into self-damped bursts of RF oscillations responsive to a relaxation oscillator which is recurringly triggered by a negative impedance device. The time at which the relaxation oscillator is triggered may be varied as a function of an analog signal to thereby produce a repetition rate modulation of the analog. Also, the negative impedance characteristic of the trigger device may be used to gain a tremendous amount of momentary amplification which provides an amount of power that is adequate to generate vast quantities of heat. Therefore, at the low voltage end of the scale, the RF generator may be used as a transmitter for walkietalkies, and at the high voltage end of the scale the RF generator may be used as an oven. In between these two ends of the scale, the generator has many other uses.

A novel high-frequency interpretation of a general purpose Op-Amp-based negative resistance for chaotic vibrations in a simple a priori nonchaotic circuit

Abstract: A novel model of general purpose operational amplifiers is made to approximate, at best, the equivalent circuit for real model at high-frequency. With this new model, it appears that certain oscillators, usually studied under ideal considerations or using many existing real models of operational amplifiers, have hidden subtle and attractive chaotic dynamics that have previously been unknown. These can now be revealed. With the new considerations, a “two-component” circuit, consisting simply of a capacitor in parallel with a nonmodified (and usually presented as a linear, negative) resistance, tends to exhibit chaotic signals. P-Spice and laboratory experimental results are in good agreement with the theoretical predictions.

Low voltage fluorescent operating circuit

Abstract: A circuit for starting and operating a low-voltage fluorescent lamp from a 120 volt AC supply. The circuit includes a choke type ballast connected in series with the lamp and inductively coupled to a pulse train generator comprising an RC energy storage circuit connected across the line and a voltage sensitive transistorized relaxation oscillator having a divider network for sensing lamp voltage. In a preferred embodiment the circuit is employed in a preheat mode of operation in combination with an electronic starter circuit comprising a PTC resistor, silicon diode and SCR series connected across the lamp.

Sensor device for railway systems

Abstract: A sensor device, which is externally supplied with power via a two-wire line and in the case of contactless influence on the two-wire line, brings about a change in the supply current, is subject in the process in terms of operation to supply voltage fluctuations. This has negative effects on at least one oscillator circuit contained in the sensor device. The sensor device according to the invention avoids this disadvantage. The sensor device consists of an oscillator circuit which can be influenced inductively and has an oscillator transistor (T1) connected as a common base, the passive components (C2, C3) being dimensioned such that strong overriding in terms of alternating voltage takes place. The oscillator transistor (T1) operates at the same time as an actuator in a direct current stabilisation circuit (R1, Z, R2). A direct voltage signal whose amplitude is to be evaluated is tapped off from an emitter resistor (R2) of the oscillator transistor (T1) and fed via a filter element (R6, C4) to a direct voltage threshold value switch (OP). The sensor device can be advantageously used as a wheel sensor in railway systems.

Voltage-controlled oscillator using complementary symmetry mosfet devices

Abstract: A voltage-controlled oscillator that is compatible with integrated circuit techniques and comprises complementary symmetry MOSFET devices to provide linear operation over several frequency decades, and exhibits high input impedance and minimum power consumption. The frequency of operation is controlled by a current source which is controlled solely by an input voltage. The constant current source linearly charges a capacitor through a bridge circuit. The bridge circuit which includes two complementary MOSFET transistors in each arm is connected across the current source and arranged so that when one transistor in an arm switches on the diagonally opposite transistor, in the other arm, also switches on. The rising voltage across the capacitor is used to change the state of a bistable multivibrator when a given threshold voltage is reached. The output of the bistable multivibrator discharges the capacitor, causes the capacitor to be charged in the opposite direction and provides an output terminal for the voltage-controlled oscillator.