The core chip used in microphone capsules is typically a Field-Effect Transistor (FET), which operates based on the field-effect principle. It is widely known for its role in impedance conversion and signal amplification inside electret condenser microphones.
FETs are characterized by:
- High input impedance
- Low noise
- High cutoff frequency
- Low power consumption
- Excellent thermal stability
- Strong radiation resistance
- Multifunctionality
- Simple manufacturing process
Because of their low charge storage effect and short reverse recovery time, FETs operate at high switching speeds and high working frequencies. Their behavior is generally linear or follows a square-law characteristic, which means intermodulation and cross-modulation distortions are significantly lower than those produced by bipolar junction transistors (BJTs).
As a result, FETs are widely used not only in microphone elements but also in a variety of amplification and digital circuits.
