An inductive proximity sensor oscillator (A) having a differential comparator (38) in combination with a negative feedback network (38) and a positive feedback network connected to the comparator. The positive feedback network (22, 36) determines the frequency and amplitude of the generated oscillations. An LC resonant tank circuit (22) is connected between a non-inverting input (30) and a fixed reference voltage (20), and a current limiting resistor (36) connected between the non-inverting input and the output of the comparator. The negative feedback network (38) provides a simple, fast and reliable start-up mechanism. It comprises a capacitor (40) connected between the inverting input of the comparator and the circuit ground and a resistor (42)

Inductive proximity sensor oscillator

A signal source for generating a well-controlled, predictable oscillating output signal within a short, predetermined and constant start-up time is disclosed The invention includes a switchable current source for selectively providing an electrical signal to a tank circuit which, in response, provides an oscillating output signal A control circuit, comprising a comparator is connected to the tank circuit for providing a control signal to the switchable current source which causes the current source to switch in response to the output signal Particular embodiments of the invention include means for controlling the amplitude of the oscillating output signal, means for controlling the transconductance of the current source, and means for starting the signal source

Signal source for use with an lc tank circuit

An apparatus monitors and controls application of three phases of alternating voltage to a load by detecting the sequence of the three phases. A switch module is operated, in response to the detected sequence, to ensure that the three phases are properly applied to the load, even if the utility lines are improperly connected. The monitoring also senses loss of a phase in which case the switch module disconnects the application of electricity to the load. The apparatus is capable of being used with different loads that operate at different peak to peak levels of alternating voltage.

Apparatus for interfacing a three phase power supply to a load

For a parallel resonant circuit comprising an inductor (4) and a capacitor (5), a source (1) of DC is connected by a switch (2). A control circuit (6) receives and processes the signal from the oscillatory circuit (3) and operates a control for opening and closing the switch (2), accordingly. For a series resonant circuit the signal to the control circuit (6) is abstracted from the single junction between the inductor (4) and the capacitor (5), and the oscillatory circuit (3) is alternately shorted and connected to a DC battery. The switch is reopened as soon as sufficient oscillation is detected.

Verfahren und vorrichtung zur erregung eines schwingkreises

An amplifier having a resonator coupled between input and output terminals thereof supplies a dot clock signal to a character generator in a television receiver. A feedback control circuit supplies DC bias to the resonator during blanking intervals that preceed lines of characters to be displayed to ensure a consistent starting phase for oscillations, removes the DC bias and supplies operating power to the amplifier during a portion of the active video period of each displayed line for sustaining the oscillations and automatically inhibits the supply of amplifier power at the end of each active line of characters to thereby provide three oscillator operating modes of PRIMED, RUNNING and OFF so as to minimize overall power consumption for the oscillator for each field of displayed characters.

Start-stop oscillator having fixed starting phase and minimized quiescent power dissipation

An electric oscillator comprising a resonant circuit wherein, after switching on the oscillator, it takes a short time to build up to a desired amplitude of oscillation. To reduce the oscillation build-up time of the oscillator, a current supply source is provided along with control elements and switching means for changing the operating mode of the oscillator from a standby mode to an oscillatory mode, and vice versa. During the standby mode a charging current is supplied to the coil of the resonant circuit so that when switching over into the oscillatory mode, the charging current to the coil is interrupted. As a result, the control elements are immediately supplied with oscillations of the desired oscillatory amplitude.

High-speed switched oscillator

The invention relates to an electric oscillator comprising a resonant circuit. After switching on such oscillators it takes a minimum time to build up an oscillatory working amplitude. To reduce the oscillation build-up time of the oscillator it comprises a current supply source, control elements and switching means for changing the operating mode of the oscillator from a standby mode to an oscillatory mode vice versa. During standby mode a charging current is supplied via the coil of the resonant circuit so that while switching on into the oscillatory mode the charging current is interrupted, and the control elements immediately can have the disposal over an oscillatory amplitude to work with.

Graham David Lill

Papers

High-speed switched oscillator

An improved oscillator