Motorola Corporation

Cts Corporation

Dale G Hall

James R Phillips

Harold W Mech

Jerry L Bohannan

Donald W Forst

Gary L Vaughn

Hank Burke

A communication device such as a pager or cellular telephone which requires battery power, uses a piezoelectric device as both a vibrating silent alarm and a battery charger.

Combined piezoelectric silent alarm/battery charger

A piezoelectric transformer with voltage feedback is disclosed. The transformer comprises a piezoelectric plate of predetermined length, width and height with a driving section formed by alternately stacking a plurality of piezoelectric ceramic layers having internal interdigitated electrode layers. A driven section including an unpolarized dielectric section, a voltage feedback section in the form of a multilayer electrode structure or an outer strip, and a normally polarized dielectric section is also disclosed. The transformer generates an output voltage at an output terminal by the piezoelectric vibration transmitted from the driving section. A feedback control circuit is connected to the voltage feedback section. The isolated voltage feedback provides feedback control to keep the transformer operating at the proper resonant frequency even as there is a change in output load of the transformer.

Piezoelectric transformer with voltage feedback

Material sensor

An improved piezoelectric material detector. The material detector (10) has a transducer structure (12) adapted to provide a certain vibration activity. A reset circuit (30) is included to minimize the possibility of false readings. And, a driving circuit (52) and detecting circuit (68) are utilized to drive and sense the presence of a material.

Piezoelectric material detector

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Cedar Crest, NM, United States of America

Dale G Hall