The core component of the condenser microphone is the polar head, which is composed of two pieces of metal film; when the sound wave causes its vibration, the different distance between the metal film causes the different capacitance, which produces the current. Because the polar head needs a certain voltage to polarize, the condenser microphone generally needs phantom power supply to work. Condenser microphone has the characteristics of high sensitivity and high directivity. Therefore, it is generally used in all kinds of professional music, film and television recording, which is very common in the studio.
　　Another kind of condenser microphone is called electret microphone. Electret microphone has the characteristics of small volume, wide frequency range, high fidelity and low cost. It has been widely used in communication equipment, household appliances and other electronic products. Electret microphone in production, the diaphragm has been high-voltage polarization treatment, will be permanently charged, so there is no need to add additional polarization voltage. In order to be portable, electret condenser microphone can be very small, so it will affect the sound quality to a certain extent. Theoretically speaking, the electret microphone and the traditional recording room microphone will not have the same size.
　　The sound picking principle of condenser microphone is to use a very thin gold-plated film as one pole of the capacitor. It is separated by a few millimeters, and there is another fixed electrode. In this way, a capacitor with several P farads is formed. The film electrode vibrates with the sound wave, causing the capacitance change and forming an electrical signal. Because the capacitor has only a few P farads, its internal resistance is very high, reaching the level of G ohm No. Therefore, a circuit is needed to convert the G ohm impedance into a general impedance of about 600 ohm. This circuit, also known as "preamplifier circuit", is usually integrated into the interior of the condenser microphone and needs "phantom power supply" to supply power to the circuit. Because of the existence of this preamplifier circuit, the condenser microphone must be powered by phantom power supply in order to work normally. Generally, the sensitivity of condenser microphone + phantom power supply is very high, which is much more sensitive than the commonly used dynamic microphone. In other words, whether the condenser microphone is used for recording on the computer or other equipment, phantom power supply is necessary, and the recorded sound will not be smaller than that of the dynamic microphone.