How does a microphone convert sound into a signal?

A microphone converts sound into a signal by vibrating a diaphragm to create an electric signal. When sound waves enter the microphone, they strike a diaphragm, which is a thin membrane that can move in response to the pressure variations created by sound. This movement alters the capacitance (in capacitor microphones) or induces a voltage (in dynamic microphones) which produces an electrical signal that corresponds to the sound waves. This electrical signal can then be amplified and processed further.

The conversion process is fundamental to how microphones work across various types; whether it's a dynamic microphone or a condenser microphone, the diaphragm’s movement is key in translating sound into an electrical format. This transformation is essential for the operation of audio recording and reproduction devices, enabling sound to be captured and played back accurately.

The other options do not accurately describe how microphones function. For instance, capturing sound digitally refers to methods used in digital recording systems but is not a primary mechanism of how microphones operate. Amplifying sound waves pertains to processing the signal post-capture rather than the conversion process itself. Filtering out background noise is more about signal processing techniques used after initial sound capture rather than the fundamental operation of a microphone.