1. Working principle of dynamic microphone
Moving-coil microphone (moving-coil microphone [Engineering Acoustics] Moving-coil microphone, moving-coil microphone) is a device that converts sound into electrical signals. The moving coil microphone is made using electromagnetic induction. When the sound wave vibrates the metal diaphragm, the coil (called the voice coil) connected to the diaphragm vibrates together, and the voice coil vibrates in the magnetic field of the permanent magnet. The induced current (electric signal) is generated. The magnitude and direction of the induced current change. The amplitude and frequency of the change are determined by the sound wave. This signal current is amplified by the loudspeaker and transmitted to the speaker, and the amplified sound is emitted from the speaker.
When the microphone receives a sound wave, it acts on the diaphragm, causing the diaphragm to vibrate, driving the voice coil to vibrate correspondingly, and the voice coil moves in the magnetic steel to generate electromotive force, and the sound signal is converted into an electrical signal.
Second, the working principle of capacitive pickup
Capacitive pickups likewise use the diaphragm to receive air vibration signals. A capacitor is formed between the diaphragm and the fixed plane electrode. The change in the distance between the two will cause the change of its capacitance. When a voltage of a fixed frequency and magnitude is applied across the capacitor, the current through the capacitor will change. Convert this current signal to output audio signal.