Keywords: US Patent 3118022 - Gerhard M. Sessler James E. West - Bell labs - electroacustic transducer - foil electret condenser microphone 1962 1964 - pages 1-3.png United States patent 3118022 of first foil electret microphone electroacoustic transducer invented by G M Sessler and J E West at Bell Laboratories in 1962 PD-USGov original upload log page en wikipedia US_Patent_3118022_-_Gerhard_M _Sessler_James_E _West_-_Bell_labs_-_electroacustic_transducer_-_foil_electret_condenser_microphone_1962_1964_-_pages_1-3 png 2007-08-31 16 55 Nasoeng 3964×1958×1 211793 bytes <nowiki>United Staten patent of first electret microphone electroacustic transducer invented by G M Sessler and J E West at Bell Laboratories in 1962 </nowiki> Electret condenser microphones Microphone schemas History of technology U S Patent drawings Transducers Bell Labs |