Can a microphone make a sound?
01Electret MIC
I. Introduction
This is an electret microphone at hand, and it includes seven ventilation holes on the front. There are two pins on the back. One of the pins is connected to the case. ·The following experiments verify whether the microphone can produce sound by applying an external signal.
2. Modify MIC
Using a hand drill, open a small hole behind the mic so that the internal FETs are exposed. Plus, I'm using a drill to expand the cavity, exposing the metal ring inside. Using AB glue, fix a metal wire to the back cover, connecting with the inner metal ring. Wait for the AB glue to solidify, and the MIC will be remodeled.
Next, solder the external electrode to the shell of the microphone and the metal ring in the middle. This allows the drive voltage to be applied between the inner metal ring and the case. Next, apply a voltage, 1kHz sine wave, to the modified microphone to see if it can produce sound.
3. Apply voltage
Using a SmartTweezer to measure the impedance of the modified microphone pin, it exhibits a capacitive characteristic of about 30pF. A sweep signal is applied to both ends of the microphone, rising from 100Hz to 1kHz within one second. Listen closely to the microphone. Unfortunately, you cannot hear any sound.
※ Summary ※
This article modified an electret microphone and applied a sinusoidal signal between the internal electret film and the outer casing to test whether the microphone could emit sound. Unfortunately, the result was that the sound emitted by the microphone could not be heard. sound.
