It receives weak analog audio signals and amplifies them to drive speakers and horns.

1. Signal Amplification: Amplifies millivolt-level audio signals to a voltage/current sufficient to drive the speakers;

2. Architecture Classification:

- Class A/B linear amplifiers: Good sound quality, but generate a lot of heat;

- Class D digital audio amplifiers: Switching type, high efficiency, mainstream for portable speakers, TVs, and car audio systems;

3. Integrated Functions: Volume control, mute, short-circuit protection, overheat protection, filtering;

4. Subcategories: Low-power headphone amplifiers, high-power car amplifiers, multimedia speaker amplifiers.