Relaxation oscillator

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

An optical and electrical relaxation oscillator using a Si homojunction structured light emitting diode

Abstract: We propose an optical and electrical relaxation oscillator making use of an S-shaped negative resistance characteristic of a recently developed light-emitting diode using a bulk silicon crystal homojunction. From simulations, we found that the voltage and optical power oscillated synchronously, and their oscillation frequency increased with increasing injection current. The synchronous oscillation was also confirmed by experimental measurements. The amplitude of the voltage was 50 Vp-p, the amplitude of the optical power was 3 mWp-p, and the maximum oscillation frequency was 34 kHz. The measured value of the spontaneous emission lifetime of a Si wafer was 900 ps, which was as short as that of direct transition-type semiconductors.

High frequency high voltage power supply preventing simultaneous transistor conduction

Abstract: A push-pull current-fed parallel resonant oscillator includes a parallel resonant LC tank circuit with one end coupled to one terminal of a DC current source via a serially connected first diode and first switching transistor and the other end of the tank circuit coupled to said one terminal via a serially connected second diode and second switching transistor. Respective capacitors (17, 21) shunt the series connections. The tank circuit inductor includes the primary of a transformer whose secondary is part of the transistor drive circuit. The circuit parameters are chosen to provide a duty cycle less than 50% and a high voltage gain of the AC tank voltage. The transistors are controlled to delay the turn-off time of the on-transistor thereby allowing a negative voltage to develop on the opposite capacitor which in turn delays turn-off of its parallel connected transistor so as to provide a dead-time (Δt 2 ) during the switching interval in which both transistors are simultaneously off. The oscillator voltage gain is dependent on the circuit parameters and the load.

Solid state timer circuit for controlling the energization time of a load

Abstract: The solid state electronic timer controls the time of load energization with a bidirectional solid state switching device. Upon the operation of a timer actuating unit, a large capacitor is charged to provide a charge for a small capacitor in a relaxation oscillator circuit. The relaxation oscillator output is supplied to gate the bidirectional solid state switching device. Since the current necessary to operate the relaxation oscillator is small, timing cycles in the range of many minutes are provided without resort to physically large capacitors.

A GaAs pressure sensor with frequency output based on resonant tunneling diodes

Abstract: We present a novel bulk semiconductor pressure sensor based on an Al/sub x/Ga/sub 1-x/As/GaAs resonant tunneling diode (RTD) with a frequency output. A relaxation oscillator is obtained with the RTD biased in the negative differential resistance (NDR) region. Pressure applied to the RTD changes the frequency of oscillation due to the shift in current-voltage characteristics. Frequency measurements have been performed on [001]-oriented RTD's with [110]-compressive uniaxial pressure. Sensitivities of up to 0.8 kHz/MPa at 113 kHz have been measured. The main feature of this sensor type is the direct frequency output obtained by using only a maximum of three components including the RTD. Using a simplified differential equation of the oscillator circuit, the pressure-dependent effects of the RTD current-voltage characteristics on the sensor output have been investigated.