Thu Nov 21 21:38:37 CST 2021
Electret microphone muaj acoustic hluav taws xob hloov dua siab tshiab thiab impedance hloov dua siab tshiab.Lub ntsiab tseem ceeb ntawm acoustoelectric hloov dua siab tshiab yog electret diaphragm.Nws yog ib tug nyias nyias zaj duab xis, nyob rau hauv uas ib txheej ntawm ntshiab kub zaj duab xis yog evaporated ntawm ib sab.Tom qab ntawd, tom qab qhov hluav taws xob ntawm qhov hluav taws xob siab hluav taws xob, muaj cov nqi anisotropic ntawm ob sab.Lub evaporated kub nto ntawm lub diaphragm yog sab nraud thiab txuas nrog lub plhaub hlau.Lwm sab ntawm lub diaphragm yog sib cais los ntawm cov hlau phaj los ntawm ib lub nplhaib insulating nyias.Nyob rau hauv no txoj kev, ib tug capacitance yog tsim ntawm evaporated kub zaj duab xis thiab cov hlau phaj.Thaum lub electret diaphragm ntsib acoustic kev co, lub teb hluav taws xob ntawm ob qho kawg ntawm lub capacitor hloov, ua rau muaj qhov sib txawv ntawm qhov sib txawv nrog kev hloov ntawm acoustic yoj.Lub capacitance ntawm lub electret diaphragm thiab cov hlau phaj yog me me, feem ntau kaum ntawm PF.Yog li ntawd, nws cov txiaj ntsig impedance yog siab heev (XC = 1 / 2 ~ TFC), txog kaum tawm megaohms lossis ntau dua.Xws li lub siab impedance tsis tuaj yeem ncaj qha nrog lub suab amplifier.Yog li ntawd, ib qho kev sib tshuam teb cov nyhuv transistor txuas rau hauv lub microphone rau kev hloov pauv impedance.FET yog tus cwj pwm los ntawm kev tawm tswv yim siab impedance thiab tsis tshua muaj suab nrov.FET feem ntau muaj peb lub electrodes: active electrode (s), grid electrode (g) thiab ntws electrode (d).Ntawm no, ib qho tshwj xeeb FET nrog rau lwm lub diode ntawm qhov chaw sab hauv thiab daim phiaj siv.Lub hom phiaj ntawm lub diode yog los tiv thaiv FET los ntawm cov teeb liab muaj zog.Lub rooj vag ntawm FET txuas nrog lub phaj hlau.Nyob rau hauv txoj kev no, muaj peb qhov tso zis kab ntawm electret microphone.Ntawd yog, lub hauv paus s yog feem ntau xiav yas xaim, qhov ntws D yog feem ntau cov hlau yas liab thiab cov hlua khi hlua khi hlua txuas lub plhaub hlau.
Post lub sij hawm: Aug-28-2023