Dr. James Edward Maceo West by Will Dennis https://padlet.com/whanebuth/188gri46k2gy A padlet about the inventor of the foil electret microphone en-us 2017-01-06 14:50:39 UTC 2021-02-22 16:17:21 UTC hello@padlet.com https://padletuploads.blob.core.windows.net/prod/161457950/951643787d0bc26026485c60ed3f3cb5/james_edward.jpg Along with Gerhard Sessler, West developed the foil electret microphone in 1962 while developing instruments for human hearing research. Compared to the previous condenser microphones, the electret microphone have higher capacitance and do not require a DC bias. West and Sessler optimized the mechanical and surface parameters of the system. Nearly 90 percent of more than two billion microphones produced annually are based on the principles of the foil-electret and are used in everyday items such as telephones, camcorders, hearing aids, baby monitors, and audio recording devices among others. West measured the acoustics of Philharmonic Hall in New York City. Recently, West teamed with Ilene Busch-Vishniac and studied the acoustic environment of hospitals showing that hospitals are in general too loud and that the noise levels affect staff and patients. whanebuth https://padlet.com/whanebuth/188gri46k2gy/wish/145702965 2017-01-06 15:12:18 UTC https://padlet.com/whanebuth/188gri46k2gy/wish/145702965 There are three major types of electret microphone, differing in the way the electret material is used:Foil-type or diaphragm-type A film of electret material is used as the diaphragm itself. This is the most common type, but also the lowest quality, since the electret material does not make a particularly good diaphragm.Back electret An electret film is applied to the back plate of the microphone capsule and the diaphragm is made of an uncharged material, which may be mechanically more suitable for the transducer design being realized.Front electret In this newer type, the back plate is eliminated from the design, and the capacitor is formed by the diaphragm and the inside surface of the capsule. The electret film is adhered to the inside front cover and the metalized diaphragm is connected to the input of the FET. It is equivalent to the back electret in that any conductive film may be used for the diaphragm.Unlike other condenser microphones, electret types require no polarizing voltage, but they normally contain an integrated preamplifier, which does require a small amount of power (often incorrectly called polarizing power or bias). This preamp is frequently phantom powered in sound reinforcement and studio applications. Other types simply include a 1.5 V battery in the microphone housing, which is often left permanently connected as the current drain is usually very small. whanebuth https://padlet.com/whanebuth/188gri46k2gy/wish/145704233 2017-01-06 15:15:50 UTC https://padlet.com/whanebuth/188gri46k2gy/wish/145704233 Electret Microphone Inventor. Ninety percent of microphones used today are based on the ingenuity of James Edward West, an African-American inventor born in 1931 in Prince Edwards County, VA. If you've ever talked on the telephone, you've probably used his invention. whanebuth https://padlet.com/whanebuth/188gri46k2gy/wish/151828864 2017-02-06 14:40:05 UTC https://padlet.com/whanebuth/188gri46k2gy/wish/151828864 whanebuth https://padlet.com/whanebuth/188gri46k2gy/wish/160292563
]]> 2017-03-15 15:49:25 UTC https://padlet.com/whanebuth/188gri46k2gy/wish/160292563 https://padlet.com/whanebuth/188gri46k2gy/wish/451721734 2020-02-27 22:46:07 UTC https://padlet.com/whanebuth/188gri46k2gy/wish/451721734