A vehicle road speed control system has a differential pressure actuated servomotor as a part of a power unit including an integral solenoid controlled valve assembly. The servomotor and valve assembly includes a servomotor output position feedback path. The solenoid valve assembly is of the repulsion armature type with the load spring coupled to the servomotor power wall to introduce position feedback. Two modifications of the valve orifice control arrangement are disclosed.

The dynamic input impedance of a feedback current amplifier is varied such that a matching to the characteristic impedance of a line feeding the amplifier is achieved. An integrated negative feedback current amplifier has at least two amplifier stages and one inverse coupling branch from the amplifier input to the amplifier output. The active element of the last amplifier stage has a divided output circuit such that the output current is divided between the inverse coupling branch and the amplif...

An episodic infusion pump apparatus with feedback control for periodically administering a pharmaceutical, such as oxytocin or the like, to induce labor in a pregnant woman. The drug is administered at periodic intervals except during labor contractions or when the fetal heartrate indicates fetal distress.

A combined feedback control system for a servo actuator including a ram that produces a mechanical displacement output of the system as directed by a position command signal. In the combined feedback control system a lever arrangement mechanically combines displacement and velocity information of the ram, and such combined information is conveniently transduced and electrically combined with the position command signal to develop an error signal that controls an electro-hydraulic valve. The latt...

A wide bandwidth characteristic is provided for use as in a negative feedback amplifier by a deposited resistor arrangement. The arrangement includes a basic feedback resistor having a high resistance value and a narrow elongated shape. Closely positioned on the same substrate and physically parallel are one or more low value resistors having the same length and with adjacent points on the respective resistors being at the same electrical potential. The feedback capacitance is greatly reduced by...

Feedback circuitry for a charge digitizer is disclosed. The feedback circuitry includes a photo-diode coupled between the input of the integrator and the biasing voltage of the photo-diode and a pulsed light source connected to the output of the multivibrator of the digitizer. The pulsed light source is operative responsive to the output pulses of the multivibrator and will actuate the photo-diode upon each pulse to discharge the integrating capacitor. Preferably, the photo-diode is specially co...

The invention is concerned with an improvement in a hydraulic steering system for an articulated vehicle of the type which comprises a main steering valve system which directs fluid introduced thereto from a fluid source to a steering motor system responsive to an output of a steering pump apparatus. The improvement comprises an articulation angle pump and an associated conduit system connecting the articulation angle pump parallel to the steering pump system to make the steering valve system re...

A power source for operating gas discharge lamps and other loads at high frequency, typically utilizing a 120 volt ac source rectified to provide a 150 volt dc input and providing a 20,000 hertz output. An inverter with current feedback in place of the conventional voltage feedback providing voltage turn off and voltage turn on in less time and providing increased base current during the conduction time for reducing the voltage-current product and heat generated in the inverter. Voltage limiting...

An amplifier circuit, comprising a capacitive-resistive network electrically connected between the input and output of the amplifier wherein the network provides equivalent capacitance between the input and output thereby providing frequency response compensation.

Metal detector of the type having a tuned sensing loop which undergoes a shift in resonance and Q when brought into proximity to metal objects. In the absence of metal objects, the detector operates in a closed loop mode in which negative feedback is utilized to offset errors and maintain the excitation signal at an optimum frequency. Upon detection of a metal object, the system switches to an open loop mode in which the excitation signal remains at the optimum frequency and the output signal va...