Showing papers on "Relaxation oscillator published in 1967"

Generation of subnanosecond pulses with bulk GaAs

Abstract: Two circuits which utilize bulk GaAs to generate baseband subnanosecond pulses are described. The first circuit is a triggered monostable pulse regenerator while the second is a free-running relaxation oscillator which produces sharp pulses at repetition frequencies which can be an order of magnitude lower than the domain reciprocal transit time. This is possible since domain formation is limited for an extended period of time between pulses due to the presence of an external inductor.

An Electric Insect Barrier Using a Neon Oscillator

Abstract: SUMMARY An inexpensive mains or battery operated relaxation oscillator is described. The output of 25 volts at 300 cycles per second is coupled to an electric barrier designed to confine insects within a given area.

Amplitude-frequency converter circuit

Abstract: 1,088,711. Detecting leaks in a vacuum system electrically. GENERAL ELECTRIC CO. April 30, 1965 [June 5, 1964], No.18375/65. Heading G1N. [Also in Division H4] In a method of detecting leaks in a vacuum system during evacuation thereof, a flow of tracer gas is directed on a localized area of the external surface 53 (Fig.4) of the system 50, and a proportion of the gas is ionized continuously and collected at an electrode 57. At a leak, tracer gas (e. g. nitrogen) is admitted and increases the ionization probability, and thus increases the magnitude of a current in an external circuit connected to the electrode 57. The current is converted in a sensor unit (circuit Fig.1 not shown) into an A. C. signal having an audio frequency that varies in accordance with the magnitude variations of said current or alternatively in accordance with the variations in the rate of change of magnitude of the current (using Fig.3 circuit in combination with Fig. 1). The audio signal is fed to ear phones whereby an operator is warned immediately of the presence of a leak as a probe 54, directing the tracer gas, scans the said surface. The ion current can either increase or decrease in response to a leak depending on whether the tracer gas is more or less readily ionizable than the gas normally present in the system 50. Instead of using the probe nozzle 54 there may be a tube, surrounding the vacuum system, having a plurality of gas emitting nozzles directed toward the system, and gas may be emitted sequentially therefrom in a programmed sequence. In the amplitude frequency converter circuit Fig. 1 (not shown) the audio signal is produced by controlling the charge and discharge rate of a capacitor (1) in series with the ear phones, the ionization current magnitude being used to change the state of (switch on and off) transistors which are effectively in parallel with the capacitor, thereby providing a relaxation oscillator the frequency of which is dependent on the amplitude of the input signal from the sensor. The claims are directed to the amplitude/frequency converter circuit. (See class H4L).

Improvements in or relating to fire detectors

Abstract: 1,057,485 Photo-electric flame detection WILKINSON SWORD Ltd, and GRAVINER MANUFACTURING CO Ltd Dec 30, 1963 [Oct 5, 1962], No 37715/62 Heading G1A A fire detection system for ships or buildings comprises a number of gas-discharge photo-cells which respond to ultraviolet radiation and are associated with capacitors C1 to form relaxation oscillators The capacitors are normally charged, and when a cell becomes ionised a neon lamp in series therewith strikes and relay RL energizes As the associated capacitor C1 discharges, the cell and neon lamp become quenched until the charge on the capacitor C1 builds up again The neon lamp thus flashes on and off Relay RL which is slugged by a shunt capacitor C2 remains up, however, and controls a ball through a further relay RLA