An amp limiter circuit is a crucial part of audio amplifiers, ensuring optimal signal levels and preventing distortion. It comprises transistors to amplify signals, resistors to control voltage and current, capacitors to filter out unwanted frequencies, and inductors to smooth out the power supply. By setting a threshold level, attack time, and release time, the limiter circuit attenuates excessive signal peaks, effectively preventing clipping and maintaining a consistent output level. This ensures a clean, undistorted audio signal, enhancing overall sound quality.