Electroacoustic transducer for generating and detecting vibrations - has spiral conductor on diaphragm between pole pieces of magnet or solenoid

摘要

The apparatus for genrating or detecting sound or ultrasonic waves or mechanical vibrations, comprises one or more spiral copper conductors. The conductors are supported on an annular syntethic material diaphragm which is supported at its inner and outer edges by respective pole pieces (2, 3) of a permanent magnet or electromagnet (1). The magnetic lines of force lie in the plane of the diaphragm at right angles to the conductors, and thus the resulting Laplace force is perpendicular to the diaphragm over its whole area. The conductors have two terminals.