Analysis of the principle and advantages of condenser microphones

Most of the microphones on the market are condenser microphones. Condenser microphones can convert sound signals into electrical signals and make full use of capacitance changes. What are the advantages of condenser microphones? What is the principle of condenser microphones?

Principle of Condenser Microphone

The condenser microphone has two metal plates, one of which is coated with an electret film (mostly polyperfluoroethylene propylene) and grounded, and the other plate is connected to the gate of the field effect transistor, the gate and the source A diode is connected between the poles, as shown in Figure 2-4. When the electret diaphragm itself is charged, the amount of surface charge is Q, and the capacitance between the plates is C, then the ground voltage U=Q/C is generated on the pole head, when it is vibrated or rubbed by airflow , Due to vibration changes the distance between the two plates, that is, the capacitance C changes, but the power Q does not change, it will cause a voltage change. The magnitude of the voltage change reflects the strength of the external sound pressure, and the frequency of this voltage change reflects The frequency of the outside sound, this is the working principle of electret microphone.

What are the advantages of condenser microphones?
1. Can convert sound directly into electrical energy signal
Condenser microphones use the principle of capacitor charging and discharging between conductors. Ultra-thin metal or gold-plated plastic film is used as a vibrating film to induce sound pressure, which changes the static voltage between conductors and directly converts them into electrical energy signals, which are practically coupled through electronic circuits. The output impedance and sensitivity are designed.

2. It can show the characteristics of original sound reproduction
Acoustics experts take the pursuit of "reproduction of the original sound" as the highest level of audio! From the analysis of the basic design principles of the microphone, it is not difficult to find that the condenser microphone not only relies on the precise mechanism manufacturing technology, but also combines complex electronic circuits to directly convert the sound into Electric energy signals have inherently superior characteristics, so they are the best choice for those who pursue "reproduction of the original sound".

3. Has an extremely wide frequency response
The diaphragm is the main component of the microphone that senses sound and converts it into electrical energy signals. The material of the diaphragm and the design of the mechanism determine the characteristics of the microphone's sound quality. Because the diaphragm of a condenser microphone can be made of extremely thin and light materials, and the induced sound pressure is directly converted into an audio signal, the frequency response of the bass can be extended to ultra-low frequencies below 10 Hz, and the treble can easily reach tens of KHz. Ultrasound, showing very wide frequency response characteristics!

The above is the relevant introduction about condenser microphones. Compared with other microphones, condenser microphones are cheaper, small in size, and can be designed into very mini microphones.

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