MINIATURE CAPACITOR ELECTRET MICROPHONE Russian patent published in 1994 - IPC

FIELD: electroacoustics. SUBSTANCE: miniature capacitor electret microphone has rectangular case with input acoustic hole in one of walls with matching preamplifier in the form of field-effect transistor put into it, two reception units each incorporating mobile and immobile electrodes insulated from each other with electret mounted on the latter. Planes of mobile electrodes are arranged in symmetry with reference to plane passing through axis of input acoustic hole, are parallel to two opposite walls of case and form acute angle which rib is located on wall of case opposite to acoustic hole. Immobile electrodes are connected in parallel to input of matching preamplifier. EFFECT: simplified design, improved operational characteristics. 4 dwg