Showing papers on "Piezoelectric motor published in 1978"

Piezoelectric polymer membrane stress gage

Abstract: Apparatus and method for detecting pressure variations because of acousticaves by modulating a preset tensile stress in a stretched thin sheet of a piezoelectric polymer. The modulation is provided by the changing stress caused by an impinging acoustic signal or the like. The piezoelectric polymer sheet under a preset tension acts effectively as a membrane resulting in a high output combined with a high resonance frequency and a wide operating frequency range.

Camera having an automatic control mechanism and piezoelectric energy conversion means

Abstract: A camera having an automatic control mechanism, for example, an exposure control mechanism, requiring electrical energy and furnishing mechanical energy. Electrical energy requirements are normally fumished by batteries or induction generators; mechanical energy is fumished by electromagnets, motors or solenoids. Such devices are generally heavy, bulky and expensive in the context of modem cameras. Batteries require replacement. Electrical energy is supplied to the automatic control mechanism by a piezoelectric generator (10; 29; 135; 210; 342) which furnishes high voltage and low current Mechanical energy is supplied by a piezoelectric electrical-mechanical transducer (14; 29; 158; 212; 352) which responds to high voltage and low current. In its preferred form, each piezoelectric element is a piszoelectric bender which supplies electrical energy when bent and bends when electrical energy is applied to it

Length-expander composite transducer and resonator excited by a perpendicular electric field

Abstract: A model is developed for length-expander composite transducers and resonators excited by a perpendicular electric field. Theoretical and experimental results are reported for several structures of resonators made with metal and lithium niobate as piezoelectric materials.