Electret microphone containing a frame shaped distance piece

摘要

An electret microphone is made of a metal electrode (3), a metallised electret film (4) and an amplifier component (8), which are contained in, and held together by, an upper and a lower half-casing (1 and 2 respectively). A frame shaped distance piece of insulating material is placed between the metal electrode (3) and the electret film (4) and sticks firmly to the contact surfaces.