Abstract: A system for measuring currents flowing through a conductor uses the current-carrying conductor itself as the measurement shunt. The voltage developed across the inherent resistance of a fixed length of current-carrying conductor is measured and scaled to provide a displayable voltage of magnitude equal to the magnitude of current flowing in the conductor. Compensation for conductor temperature rise can be utilized, as can a multimeter accommodating various conductor materials and/or sizes.

Abstract: A piezoelectric force/pressure sensor capable of detecting the magnitude of static and dynamic force or pressure applied thereto, utilizes first and second transducers each having a piezoelectric member with opposed first and second surfaces; an electrode fabricated upon each of the first and second surfaces of each of the first and second piezoelectric members; and a member fabricated of a material of known resiliency having first and second opposed surfaces each attached to one of the electrode-bearing first and second surfaces of a different one of the piezoelectric transducers. A first of the piezoelectric transducers is excited to vibrate in the thickness mode. The vibrations are coupled through the interposed elastic middle layer and are transformed to provide an electrical output from the sensor which is responsive to the force/pressure applied along the axis of the transducer-resilient member-transducer sandwich.

Abstract: A current sensor, integratable with power switching and control circuitry on a common substrate and insulatable from current-carrying conductors, utilizes a piezoelectric element located between a pair of current-carrying conductors. The conductors carry a current flowing in the same direction, causing an attractive force therebetween to act upon the piezoelectric element and generate a voltage therein proportional to the square of the conductor currents. Use of a pair of sensors, each in a different portion of a half-bridge circuit, and associated electronics for providing a sensor output proportional to the instantaneous value of the sensed current, is also described.

Abstract: A system for protecting an electrical component, drawing current from a power source, utilizes a sensor providing an output signal proportional to the square of the load component current. The squared-current signal, when greater than a squared-normal-current signal, is integrated and compared to a current squared-time value. A system output is enabled if the load component instantaneous i.sup.2 t value is greater than the current squared-time value set at the comparator, to remove the current flow to the protected component.

Abstract: A steered beam B-scan ultrasonic imaging system has a linear transducer array divisible into multiple sub-arrays of transducer elements each operable to perform a sector scan, with the origin points displaced longitudinally along the array between sector scans. The system performs overlapping sector scans and is capable of imaging randomly oriented specularly reflecting targets. Time delays in the transmitting and receiving channels to steer the transmitted beam and to focus the received echoes are provided by digital techniques, by reversible digital shift registers, or by charge coupled device delay lines. The multiple sector image is displayed in real time in an intensity versus displacement format on a cathode ray tube.