This is a small microphone module equipped with a 100 Hz to 10 kHz microphone and a 60x microphone preamplifier. It amplifies voices, clapping, door knocks, and other sounds to a level sufficient to be picked up by a microcontroller's ADC. It can operate from 2.7 V to 5.5 V. This board reads the sound waves between two conductive plates (vibrating and fixed) within the microphone and converts them into an electrical waveform to read the amplitude. The converted electrical signal is amplified and then picked up by the ADC of your microcontroller.