Electret Condenser Microphones (ECM)
ECM series
The Electret Condenser Microphone (ECM) is a mature audio technology that utilizes a permanently charged electret material to store an electric charge and generates signals by varying capacitance through vibration.
Working Principle
1. Electret Characteristics: It employs an electret internally—a type of ferroelectric material capable of permanently retaining an electric charge—thereby providing a fixed charge without the need for an external high-voltage polarization source.
2. Capacitance Variation: When sound waves cause the thin diaphragm to vibrate, the distance between the diaphragm and the backplate changes; this alters the capacitance and converts the acoustic energy into an electrical signal.
Advantages and Disadvantages
1. Advantages: Low cost and highly mature technology; compact size, stable sensitivity, and wide frequency response.
2. Disadvantages: The structure is relatively delicate, making it sensitive to high sound pressure levels or severe physical impact. It is susceptible to environmental noise (such as fan noise), and its heat resistance is somewhat inferior to that of MEMS microphones regarding modern automated Surface Mount Technology (SMT) manufacturing processes.
