ELECTRET CONDENSER MICROPHONE

摘要

PURPOSE: An electret condenser microphone is provided to mount directly the electret condenser microphone on the positive electrode and a negative electrode of a printed circuit board by projecting the positive electrode and the negative electrode. CONSTITUTION: A plurality of passing holes(200a) is formed in a case(200). A vibration plate(210) is installed on the inside of the passing holes(200a). The vibration plate(210) is vibrated by sound waves received through the passing holes(200a). The sound waves are converted to mechanical signals by the vibration plate(210). The mechanical signals are converted to electrical signals by a back plate(208). The back plate(208) is installed on an upper portion of a spacer(214) of the vibration plate(210). A plurality of through-holes(208a) is formed on the back plate(208). The vibration plate(210) includes a vibration layer(212). An electric shielding member(220) is installed on an inner circumference of the case(200). A conductive ring electrode(222) is installed on an inner circumference of the electric shielding member(220). A field effect transistor(FET) and a capacitor(C) are installed on a printed circuit board(224).