Isodynamic electromagnetic acoustic transducer with stressed diaphragm.

摘要

An electromagnetic acoustic transducer having a substantially "flat" diaphragm bears a spiral or meandering current conductor. The diaphragm is positioned adjacent one or more fixed permanent magnets (12, 18) which create a magnetic field orthogonal to the current path of the conductor such that the vector force is perpendicular to the plane of the diaphragm. The diaphragm (13) is stressed to form a bowed shape permitting damping elements to be provided without deleteriously affecting the resonance of the transducer.