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Microphone-speaker

Active noise suppressing headphones try to keep the pressure constant or force it to follow some wanted program material. It succeeds in a chamber which is so small that only one waveform (=soundwave ...
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How to connect an external dynamic microphone to your smartphone (Android)

Sorry. I had a broken transistor. Everything works. I checked several transistors, 2n2222, BC547, etc. You can probably use any NPN transistor and it will work. Instead of a resistor, I used a 1 ...
m72's user avatar
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Noise decibel meter - how to convert MAX4466 voltage output to unweighted dB(SPL)

You can factor in the sensitivity of the mic at any point you desire. You know that the mic, when fed with some sound amplitude, either in Pa or dB(SPL), the mic outputs some voltage in V or dB(V), ...
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Sound activated LED

There are two 100 nF caps in the schematic. This is why reference designators are so important. Probably, the one in the question is the coupling capacitor (sometimes called a blocking capacitor, but ...
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Sound activated LED

The 100nF is called a bypass capacitor. It's role is to block the DC bias when there is no signal. Without it, Q1 stays conducting no matter what the microphone is doing. It essentially passes the ...
MOSFET's user avatar
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