Capacitive microphone for sound level meter
A condenser microphone is a great microphone for recording, and its uses include solo singing, saxophone, flute, steel pipe or woodwind instruments, acoustic guitar or acoustic bass. The condenser microphone is suitable for any use that requires sound quality and clarity. Due to its sturdy and durable structure and ability to handle high sound pressure, condenser microphones are a great choice for on-site sound reinforcement or recording.
Another commonly used condenser microphone is called an electret microphone, which has the characteristics of small size, wide frequency range, high fidelity, and low cost. It has been widely used in electronic products such as communication equipment and household appliances. The diaphragm of an electret microphone has already undergone high-voltage polarization treatment during production, which will permanently carry a certain charge, so there is no need to add additional polarization voltage. For portability and other requirements, electret condenser microphones can be made smaller, which will to some extent affect sound quality.
The principle of capacitive microphones
The sound pickup principle of a condenser microphone is to use an extremely thin gold-plated film as one pole of the capacitor, which is separated by a few millimeters and has another fixed electrode, forming a capacitor of several P farads. The thin film electrode vibrates with the sound wave, causing the capacitance to change and forming an electrical signal. As this capacitor only has a few P farads (1 farad=1000000000P farad), its internal resistance is extremely high, To reach the level of G ohms (1G ohms=100000000 ohms), a circuit is needed to convert the impedance of this G ohms into a universal impedance of around 600 ohms. This circuit, also known as a preamplifier circuit, is usually integrated inside a condenser microphone and requires a fantasy power supply to power the circuit. We usually refer to the power supply required for condenser microphones as fantasy power supply, which generally includes 12V, 36V, 48V, etc., depending on the microphone situation. It is precisely because of the existence of this preamplifier circuit that condenser microphones must be powered by a fantasy power supply in order to function properly. Capacitor microphones and fantasy power supplies generally have high sensitivity, much more sensitive than commonly used dynamic microphones. In other words, whether a condenser microphone is used for recording on a computer or other device, a fantasy power supply is necessary, and the recorded sound is no smaller than that of a dynamic microphone.
