A brief discussion on the operating points of Class B amplifiers
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A brief discussion on the operating points of Class B amplifiers

Posted Date: 2024-02-06

Class B amplifier is a type of amplifier also known as Class B amplifier. Its working principle is that the positive and negative half cycles of the input signal are amplified and output in turn by the two "arms" of the push-pull output stage. The conduction time of each "arm" is greater than half a cycle and less than one cycle. The advantage of Class B amplifier is high efficiency, but the disadvantage is that it will produce crossover distortion.

A type of distortion unique to Class B amplifiers is called crossover distortion, which is caused by the fact that the positive and negative half cycles of the signal are amplified by two different sets of devices respectively, and the waveforms on the positive and negative sides cannot be smoothly connected.

Class B amplifier operating point

The operating point is set to the collector voltage value when the collector current is 0, and only half of the AC signal plays the role of output current. Therefore, the output current waveform is different from the input current waveform. If a push-pull connection is used (see figure), the cut-off half can be amplified with another transistor and the input waveform can be reproduced.

What situations are Class B amplifiers mainly used for?

Class B amplifiers are mainly used in audio amplification applications, especially audio amplification applications that require high power output. Here are some of the main use cases:

1. Sound system: Class B amplifiers are widely used in sound systems, including home theater systems, professional audio equipment and stage audio equipment. Class B amplifiers provide high-power audio amplification to make music, movie sounds, or public broadcasts clearer and more powerful.

2. Car audio: Class B amplifiers are also commonly used in car audio systems. Car audio needs to provide powerful sound output in a noisy cabin environment. Class B amplifiers can meet this need and ensure that the sound quality is not lost.

3. Professional audio equipment: Class B amplifiers are commonly used in professional audio equipment, such as music recording studios, studios, and live audio consoles. These occasions require high fidelity and audio quality, and Class B amplifiers can provide low-distortion, high-fidelity audio amplification effects.

4. Concerts and music performances: Class B amplifiers are widely used in concerts and music performances to amplify musical instruments, vocals and music effects. Since these occasions require high power output, Class B amplifiers can meet this demand and provide clear and powerful sound effects.

Class B amplifiers are suitable for audio amplification applications that require high power, high fidelity and low distortion. Whether it is home theater, car audio, professional audio equipment, concerts, music performances, etc., Class B amplifiers can provide high-quality audio amplification effects.

Review Editor: Huang Fei


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