Piezoelectric transducer

An electroacoustic transducer comprising:

• a pair of circumferentially polarized hollow piezoelectric cylinders, said pair of cylinders having equal diameters connected concentrically end to end, each one of said pair of piezoelectric cylinders formed from a first material having selected thickness and characteristics to produce a desired capacitance;
• a pair of radially polarized hollow hemispherical piezoelectric end caps having major diameters essentially equal to the diameter of said cylinders, said caps attached to the outside ends of said pair of cylinders, each one of said pair of piezoelectric end caps formed from a second material having selected thickness and characteristics to produce said capacitance;
• and
• a pair of leads connected to said transducer, said pair of cylinders and said pair of caps being interconnected electrically in a series-aiding relationship with respect to said pair of leads.

An electroacoustic transducer having high acoustic-to-electric energy conversion per unit volume comprising:

• 1. a pair of output terminals;
• and
• 2. a body having
• (a) a hollow cylindrical center section formed from a first type of active piezoelectric material, such section having two cylinders mechanically connected concentrically end to end, said two cylinders circumferentially polarized with opposite polarities and electrically connected in a series-aiding manner;
• and
• (b) hemispherical end sections formed from a second type of active piezoelectric material, said two end sections radially polarized with oppostie polarities and electrically connected with said central section in a series-aiding manner;
• wherein said pair of output terminals is connected to said body so that the entire external surface area of said body is effective in producing electrical energy.

An electroacoustic transducer having high volumetric efficiency of acoustic-to-electric energy transfer for use in hydrophone thin line arrays comprising:

• a first hollow hemispherical radially polarized piezoelectric active element having a selected electrical sensitivity;
• a first hollow cylindrical circumferentially polarized piezoelectric active element having an inside diameter essentially equal to the major inside diameter of said first hemispherical element having essentially said selected electrical sensitivity and having an opposite polarization from said first hemispherical element, a first end of said first cylindrical element nonconductively secured to the major diameter face of said first hemispherical element;
• a second hollow cylindrical circumferentially polarized piezoelectric active element having a diameter essentially equal to the diameter of said first cylindrical element having essentially said selected electrical sensitivity and having an opposite polarization from said first cylindrical element, a first end of said second cylindrical element non-conductively secured to the second end of said first cylindrical element;
• a second hollow hemispherical radially polarized piezoelectric active element having a major inside diameter essentially equal to the inside diameter of said second cylinder having essentially said selected electrical sensitivity and having an opposite polarization from said second cylindrical element, the major diameter face of said second hemispherical element non-conductively secured to the second end of said second cylindrical element;
• and
• a pair of conductors connecting to said transducer wherein said elements are interconnected electrically in a series-aiding relationship with respect to said pair of conductors and said oppositely polarized hemispherical elements cause cancellation of electrical signals produced by acceleration forces acting along the longitudinal axis of said transducer.