The main function of the power amplifier is to amplify the power of the signal, so that it can reach a large level, so that the signal is effectively passed to the load. It can convert low -power signals to high -power signals to meet specific application needs.
Power amplifier is generally divided into different types such as class A, class B, class AB, class D, etc. Each type of power amplifier has its specific working principles and performance characteristics. Among them, the A -type power amplifier has the characteristics of high -line and sound quality, but the power efficiency is relatively low. The advantages of power amplifier; D power amplifier use digital switching technology, which has the characteristics of high efficiency and low power consumption.
In addition to the power of the magnification signal, the power amplifier should also have the characteristics of stability, linearity, low incomation, and high efficiency to ensure the accurate magnification and transmission of the signal.
The power amplifier has been widely used in the fields of audio equipment, communication systems, radio and television, car audio, etc., providing a powerful signal amplification function for various electronic equipment.
Power amplifier is usually divided into the following three types:
1. A -type A power amplifier: A -type A power amplifier is a linear amplifier. Its output transistor or pipes magnify the entire input signal cycle, regardless of the amplitude of the input signal. It has the characteristics of high linear amplification and excellent sound quality, but the power efficiency is relatively low, because most of the time, the power transistor or tube is in a diverse state.
2. B power amplifier: The B power amplifier uses a pair of complementary output transistors or pipes to handle the positive half week and negative half a week of the input signal. When there is no input signal, it is in a close state. Only when the input signal exceeds a certain threshold, the other way output is turned on, thereby realizing power magnification. The B power amplifier has high power efficiency, but there is a certain distortion problem because cross distortion may occur during the switching process.
3. AB power amplifier: The combination of AB power amplifier is a combination of A power amplifier and a type B power amplifier. It adds a certain bias current to the bias point of the output transistor or tube, so that the output transistor or tube is partially turned on when there is no input signal. In this way, the AB power amplifier has high linearity and sound quality, but also relatively high power efficiency.
These three types of power amplifiers have their own advantages and characteristics in different application scenarios. Choosing a suitable type according to needs can meet specific power magnification requirements.
What is the external parameter characteristics of power amplifier
The external parameter characteristics of the power amplifier refer to the impact of external circuits or systems connected to the power amplifier. The following are some common power amplifiers external parameters:
1. Input impedance: The input impedance of the power amplifier refers to the impedance of the input end of the input terminal of the input signal source of the input signal source. Appropriate input impedance matching can ensure the maximum signal transmission efficiency and minimum signal reflection.
2. Output impedance: The output impedance of the power amplifier refers to the impedance of the output end of the power amplifier in the circuit or device of the output load. Low output impedance can effectively drive the load and reduce signal distortion.
3. gain: The gain of power amplifier refers to the voltage or power ratio between the output signal between the input signal and the input signal after the amplifier. The gain can be adjusted according to the needs of the application to obtain the required amplification effect.
4. Frequency response: The frequency response of the power amplifier indicates its capacity in different frequency bands. The frequency response should be kept flat within the required operating frequency range to avoid signal distortion and attenuation.
5. Blind inhibitory: The inhibitory ability of the power amplifier within the specified frequency range, that is, the blocking zone. The barrier inhibitory ability determines the degree of suppression of the power amplifier to the signal other than the target frequency band to ensure a pure output signal.
6. Power stability: The sensitivity of the power amplifier to the fluctuation of the power supply voltage. The power amplifier with good power stability can maintain stable working performance under unstable power conditions.
These external parameter characteristics are closely related to the design and application of power amplifier, which affects its performance and applicability. It is essential to understand and consider these characteristics when selecting and using power amplifiers.