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 force/flash pressure sensor utilizes a stack of annular rings of a magnetoelastic material. One major stack surface is supported at a plurality of points having substantially equal angular displacement therebetween. A member, moving along the axis of the ring stack responsive to an axial force, or pressure, to be measured, presses a different set of points against the opposite stack surface, to distort the ring stack and alter the magnetic flux density saturation magnitude thereof. The plurality of points in abutment with each of the opposite major stack surfaces is advantageously equal; a number of different configurations for applying force (pressure) along the axis of the ring stack are described.

Abstract: A low cost hook-on ammeter for consumer use includes a split core to be clipped around a conductor. Secondary turns on the core actuate a liquid crystal digital display to indicate alternating current amplitude in the conductor. The liquid crystal display segments may be connected to individual taps on the secondary winding, or to taps on a resistive divider network connected across the entire secondary winding. As current in the conductor increases, secondary voltage increases, turning on an increasing number of segments of the liquid crystal display accordingly.

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: Radiant-energy heating and/or cooking apparatus has an infrared-wavelength radiation-producing element, a reflector for concentrating the infrared radiation and a coverplate through which the concentrated radiation is transmitted to a recipient material, e.g. foodstuffs to be cooked. The coverplate has first and second surface members separated from one another by a honeycomb of tubes; the members and tubes are fabricated of an infrared-transmissive material. The resulting honeycomb coverplate has low infrared absorption and great mechanical strength capable of withstanding severe thermal shock.

Abstract: A low cost hook-on ammeter for consumer use includes a split core to be clipped around a conductor. Secondary turns on the core actuate a liquid crystal digital display to indicate alternating current amplitude in the conductor. The liquid crystal display segments may be connected to individual taps on the secondary winding, or to taps on a resistive divider network connected across the entire secondary winding. As current in the conductor increases, secondary voltage increases, turning on an increasing number of segments of the liquid crystal display accordingly.

Abstract: A low cost volt/ampere meter for consumer use employs a single liquid crystal bargraph display and a simple voltage divider network to display both line voltages and appliance currents encountered in a residential environment. The instrument employs standard line voltage prongs on one end and a socket for accepting standard line voltage prongs on the other end. A range switch connects the instrument to read either voltage across the meter prongs or current through the prongs. When the prongs are inserted into a duplex receptacle and an appliance is plugged into the meter socket, current drawn by the appliance will be displayed on the bargraph when the range switch is selected to read amperes.

Abstract: A switching circuit having hybrid contactors connects the three output lines of a 3 phase AC power source to three input lines of a load, such as a motor and the like. A single pair of relay contacts is used to directly connect one output line of the AC power source to one input line of the load, whereas each of the other two phases of the AC power source are supplied to the load by one of a pair of pilot relay contacts in series with a diode-shunted one of a pair of master relay contacts. Only two extra pilot relays are used to provide a reversing function. The switching circuit further includes a zero-crossing detector, a phase-sequence detector, a control circuit including four flip-flops arranged in a tumble-down chain and a single distribution circuit having a data select circuit. The control circuit causes the making and breaking of the contacts at particular times, and in a sequence, such that arcing is prevented.

Abstract: Temperature indicating apparatus for sensing overheating at a pair of terminals on an electrical power line comprises a neon gas-filled glow tube and a thermistor electrically coupled in series across the terminals, with a resistor electrically coupled in parallel with the glow tube. The thermistor is thermally coupled to the terminations so that an excessive temperature rise at either terminal decreases the thermistor resistance to a level at which sufficient voltage appears across the glow tube to ignite the glow tube and provide a visual indication of overheating. The circuit readily lends itself to a plug-in type configuration if the terminals to be monitored are in a duplex receptacle, or to employment in a cube tap.

Abstract: Highly linearized and interchangeable networks, each having at least one non-linear resistive element for sensing the magnitude of a physical parameter, such as a thermistor for measuring temperature, have a specified network resistance at a particular value of sensed parameter within a desired sensed parameter range, and also have a predetermined resistance-versus-sensed-parameter slope. The network includes at least one fixed resistor for each resistive sensing element.

Abstract: The evaporating area of a heat pipe or thermosiphon evaporator is used as the thermal sink for one face of an electrically isolated substrate upon the opposite face of which are mounted and interconnected one or more power semiconductors and other components requiring cooling. Both sides of semiconductor devices mounted on the isolating substrate may be cooled while allowing each of a plurality of different combinations of electrical devices and/or interconnections to be achieved.

Abstract: A high frequency inverter power supply includes a high power inverter section powered by substantially unfiltered rectified a.c., and a control section including rectifier and filter means for providing substantially pure d.c. to maintain continuous instantaneous control over the high power inverter section. High frequency transformer means and optional output rectifiers and filters provide for a.c. or d.c. output.

Abstract: A temperature responsive resistor is thermally connected to a body of metal oxide varistor material in transient suppression and other applications. In the event of excess energy dissipation in the varistor, the temperature of the thermally responsive resistor increases to provide a trigger signal to a triac or other similar electronic switch which may be utilized to provide an alarm, provide increased cooling to the varistor body, to divert, or limit current flow from the varistor.Current flow through the temperature responsive resistor may be provided from a third terminal on the metal oxide varistor in which case the circuit is responsive to both total energy dissipation and peak energy dissipation levels in the varistor.

Abstract: A low cost magnetic circuit and method of making the same are disclosed. The magnetic circuit comprises an integral magnetic core having at least four legs in a closed magnetic path, at least one leg thereof with a circular cross section and a bobbin rotatably disposed about the circular portion for containing a coil winding. The coil is formed by rotating the bobbin while holding the core stationary.