Oceana Sensor Technologies, Inc.

Isaak Baber

Richard W Lally

Mark Frederick Bocko

Donald E Kennamer

William Simmons

Joseph E Pegg

The present invention is directed to an apparatus and method for a measurement system for the testing of transducers, and more particularly to the testing of piezoelectric transducers. The measurement system includes a transducer, a feedback amplifier coupled to the transducer and a signal processing circuit coupled to the output of the amplifier. The method of testing the transducer includes coupling the test signal to the transducer, disabling the amplifier, and measuring the response of the transducer to the test signal with the test processing circuit. The circuit itself used for performing this method includes a piezoelectric transducer, an amplifier, including a feed-back circuit coupled to the amplifier for amplifying the output of the transducer, a power source coupled to the amplifier, a signal source generating a test signal having a frequency spectrum at least overlapping the self resonant frequency of the transducer coupled to the transducer, and a switch coupled to the amplifier capable of disabling the amplifier.

Transducer in-situ testing apparatus and method

The present invention provides an apparatus and method for in-situ testing of transducers, and more particularly to the testing of piezoelectric transducers including piezoelectric accelerometers. Circuits, measurement techniques, and interpretative algorithms to enable in-situ testing of piezoelectric accelerometers are described. Accelerometers that employ a piezoelectric material to convert mechanical strains into electronic signals are reciprocal electromechanical transducers. In such transducers the electrical output impedance of the sensor is dependent upon the electrical and mechanical parameters of the sensor. The procedure described in this disclosure includes methods of measuring the transducer electrical output impedance as a function of frequency and the extraction of the electrical and mechanical transducer parameters from the measured data. The measured values of the transducer parameters may be interpreted to provide an indication of the operational status of the transducer. In addition to allowing verification of correct transducer performance, a range of failure conditions and degradations may be inferred from the transducer parameter values.

A method of manufacture and a piezoelectric transducer are provided having a housing whose interior contains a piezoelectric element having radially spaced surfaces which undergo relative shear and produce an electrical signal in response thereto, an outer radial surface of the piezoelectric element being soldered to the interior of the housing, and an inner radial surface of the piezoelectric element is soldered to the outer surface of a stress/strain transmitting element. The solder alloy used shrinks less than &rarr;2.5% solidification. The subassembly made up of the piezoelectric element and the stress/strain transmitting element is provided with a passage to permit escape of gas from a chamber above the piezoelectric member which may be present from vapors attendant soldering.

Method for fabricating a piezoelectric transducer

A method of manufacture and a piezoelectric transducer are provided having a housing whose interior contains a piezoelectric element having radially spaced surfaces which undergo relative shear and produce an electrical signal in response thereto, an outer radial surface of the piezoelectric element being soldered to the interior of the housing, and an inner radial surface of the piezoelectric element is soldered to the outer surface of a stress/strain transmitting element. The solder alloy used shrinks less than 2.5% at solidification. The subassembly made up of the piezoelectric element and the stress/strain transmitting element is provided with a passage to permit escape of gas from a chamber above the piezoelectric member which may be present from vapors attendant soldering.

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Virginia Beach, VA, United States of America

Isaak Baber