Abstract: Disclosed herein is an electronic switch that comprises a pressure sensitive bridge array adapted to monitor pressure and activate an indicator when the monitored pressure exceeds a predetermined value indicative of a dangerous condition. The electronic switch further comprises a monitoring circuit adapted to test the overall operability of the pressure sensitive bridge array and its accompanying electronics control circuitry.

Abstract: A high temperature pressure sensing system (transducer) including: a pressure sensing piezoresistive sensor formed by a silicon-on-insulator (SOI) process; a SOI amplifier circuit operatively coupled to the piezoresistive sensor; a SOI gain controller circuit including a plurality of resistances that when selectively coupled to the amplifier adjust a gain of the amplifier; a plurality of off-chip contacts corresponding to the resistances, respectively, for electrically activating the corresponding resistances and using a metallization layer for the SOI sensor and SOI ASIC suitable for high temperature interconnections (bonding); wherein the piezoresistive sensor, amplifier circuit and gain control circuit are suitable for use in environments having a temperature greater than 175 degrees C. and reaching between 250° C. and 300° C., and wherein the entire transducer has a high immunity to nuclear radiation.

Abstract: A high temperature pressure sensing system (transducer) including: a pressure sensing piezoresistive sensor formed by a silicon-on-insulator (SOI) process; a SOI amplifier circuit operatively coupled to the piezoresistive sensor; a SOI gain controller circuit including a plurality of resistances that when selectively coupled to the amplifier adjust a gain of the amplifier; a plurality of off-chip contacts corresponding to the resistances, respectively, for electrically activating the corresponding resistances and using a metallization layer for the SOI sensor and SOI ASIC suitable for high temperature interconnections (bonding); wherein the piezoresistive sensor, amplifier circuit and gain control circuit are suitable for use in environments having a temperature greater than 175 degrees C. and reaching between 250° C. and 300° C., and wherein the entire transducer has a high immunity to nuclear radiation.

Abstract: An electronic switch of the type uses a piezoresistive Wheatstone bridge configuration to sense pressure. The output of the Wheatstone bridge is applied to an electronic control circuit which contains a comparator. The comparator monitors the output of the bridge and if the output voltage of the bridge exceeds a predetermined value, as indicated by the comparator, a switch is closed to illuminate a lamp indicating to the operator that the pressure has been exceeded. One terminal of a resistor is connected to an output of the bridge. The other terminal of the resistor is coupled to a switch which when operated, causes the resistor to be connected in parallel with one of the arms of the bridge, thereby producing an imbalance of the bridge.

Abstract: A gas density transducer including: a piezoresistive bridge sensor operative to provide an output indicative of an applied pressure, a computing processor having multiple inputs and at least one output, with the output of the bridge sensor coupled to an input of the processor; a temperature sensor coupled to an input of the processor for providing at an output a signal indicative of a temperature of the bridge sensor, the output of the temperature sensor coupled to an input of the processor; and, at least one memory accessible by the processor and having stored therein: compensation coefficients for compensating the output of the bridge sensor for temperature variation; gas specific coefficients of the Van der Waal's equation; and, code for providing at an output of the processor a signal indicative of a gas density when the bridge is subjected to a gas containing environment.

Abstract: There is disclosed an electronic single pole double throw switch which completely replaces a prior art mechanical switch. The mechanical switch normally exists in a suitable vehicle, such as an aircraft or any device, but basically has three output terminals. Two terminals are associated with a first and a second lamp, which lamps have one terminal coupled to an operating voltage. Essentially, in order to replace the mechanical switch, an electronic switch also is wired to the three terminals exactly as a mechanical switch would be so wired. The electronic switch has two states. In each state, one of the lamps is on and the corresponding switch is closed. In this state, the other lamp is off, with its corresponding switch open. This operation is the same operation as that of the mechanical switch. In the electronic switch, the voltage, which is at the output terminal of the lamp that is off, is utilized to drive a low voltage regulator which operates electronic circuitry associated with the electronic switch.

Abstract: A transducer is implemented to operate with transmitted frequency signals. These transmitted signals provide a bias potential to the transducer and enable the transducer to transmit a transducer output signal to a remote location. The transducer has an antenna for receiving transmitted signals. The antenna is coupled to a rectifier circuit; the rectifier circuit is operative to provide a DC voltage in response to said received transmitted signals. This DC voltage is applied to the piezoresistive array via a switching arrangement coupled between the array and the rectifier circuit. An interface circuit controls the switching arrangement to enable DC bias to be applied to the array in a first mode and to remove the bias in a second mode.

Abstract: An electronic switch of the type uses a piezoresistive Wheatstone bridge configuration to sense pressure. The output of the Wheatstone bridge is applied to an electronic control circuit which contains a comparator. The comparator monitors the output of the bridge and if the output voltage of the bridge exceeds a predetermined value, as indicated by the comparator, a switch is closed to illuminate a lamp indicating to the operator that the pressure has been exceeded. One terminal of a resistor is connected to an output of the bridge. The other terminal of the resistor is coupled to a switch which when operated, causes the resistor to be connected in parallel with one of the arms of the bridge, thereby producing an imbalance of the bridge.

Abstract: An improved gas leak detection apparatus is disclosed for detecting a leak in a gas containing vessel of constant volume which compensates for deviations in behavior of a contained gas from an ideal model. The apparatus incorporates a pressure transducer, an amplifying means and a feedback means and operates to effectively and accurately model the van der Waals equation of state for gasses. The apparatus is adaptable for operation with any number of different gases by simply changing the values of specific circuit elements. The output of the apparatus is proportional to the total number of moles of gas present in the containment vessel at any particular time, and will thus indicate a leak from the vessel upon a reduction in that number of moles, absent an intentional reduction of the mass of gas in the vessel.