Amplifier classes refer to the different categories of electronic amplifiers based on their operation and efficiency. The most common classes include Class A, Class B, Class AB, and Class D. Class A amplifiers provide high linearity and sound quality but are less efficient, while Class B amplifiers are more efficient but can introduce distortion. Class AB combines features of both, offering a balance between efficiency and sound quality. Class D amplifiers use pulse-width modulation for high efficiency, making them popular in portable and battery-operated devices. Each amplifier class has its own advantages and disadvantages, making them suitable for different applications. For instance, Class A amplifiers are often used in high-fidelity audio systems, while Class D amplifiers are favored in subwoofers and portable speakers due to their compact size and efficiency. Understanding these classes helps consumers choose the right amplifier for their specific needs, whether for home audio, professional sound systems, or personal devices.