Automotive power amplifier (Power Amplifier) ie cars power amplifier for amplifying power car audio, its task is to weak electrical signals from the source are amplified to drive the speaker sound. Car achieve the desired effect. Pre-amplified by the power amplifier voltage level, driver stage, power amplifier stage, a speaker, etc., it is pre-stage voltage amplifier stage. The last one is a power amplifier stage, the pre-stage power-amplifies the signal sent to obtain sufficient power output to the speaker, the driver stage is required to provide large power output stage power source of the input signal. .
1 car amplifier Category
First, according to the type of sub-power amplifier
1. The tube amp; using tube amplifier.
2. Stone; is the use of a transistor amplifier.
Second, their conductively points
1, A Class A amplifier known as Class amplifier
It is an output stage two transistors foreverIn a conducting state, regardless of whether they are signal input current to maintain conduction, and these two currents is equal to the peak value of the alternating current, then flows into the AC signal at the maximum load conditions. When no signal, the same amount of current flow in each of the two transistors, so there is no imbalance in the current or voltage at the output of the center point, so no input current speaker. When the signal tends to a positive electrode of the output transistor of the line above the allowable current flows more, the bottom output transistor is relatively reduced current, since the current imbalance begins, and then flows into the push speaker sound speaker.
A class amplifier works best linearity, the output transistors are each amplified signal full-wave, complete absence of crossover distortion, even if administered without negative feedback, it is still very low open loop distortion , it is called the best sound amplification circuit design. But this design pros and cons, A class amplifier put the biggest drawback is low efficiency, because there is still no signal when current flows in full, all power to a high heat. When increasing the signal level, and some may enter the power load, but many still converted into heat.
A class amplifier is ideal for music playback, sound can provide a very smooth, mellow warm, with open transparent treble, these advantages sufficient to compensate for its shortcomings. Class A power amplifiers heat staggering, in order to effectively deal with heat problems, class A power amplifier must be large radiator. Because of its low efficiency, power supply must be able to provide sufficient current.
Class A power amplifier power supply capacity of at least enough for a 25W 100 Watt class AB use. Therefore, size and weight than the Class A Class AB large machine, which makes the manufacturing costs, the price is expensive. Generally, A class amplifier is about twice the price of the same power amplifier in class AB or more.
2, also known as B class B amplifier amplifier
The way it works when no signal is input, power is not consumed because the transistor is non-conductive. When a signal, each amplifying the output of each half wave tube, one from each other by an alternate completion of a full-wave amplification, when both output transistors will work rotation crossover distortion occurs, thereby forming a non-linear. Less pure class B amplifier, because at very low signal distortion is very serious, so crossover distortion make the sound becomes rough. Allow the use of smaller heat sink.
3, AB class amplifier
Compared with the former two types of amplifier,Class AB amplifiers can be said to compromise on performance. Class AB amplifiers are usually two biased when no signal small amount of current through the output transistor. It is used in class A mode of the signal h, optimum linearity, when the signal is increased to a level automatically converted to Class B mode of operation to achieve higher efficiency.
Normal 10 watt class AB type A work about 5 watts or less, since the power required while listening to music only a few watts of class AB power amplifier is most of the time use a Class A power amplifier works mode, only to category B in a strong voice when music transients occur. This design can achieve excellent sound quality and reduce the efficiency of heat, it is a rather logical design. Some of the class AB amplifier bias turned up very high to make it in a wider power range in class-A operation, the sound nearly pure class A machine, but also a relative increase in amount of heat generated.
4, also known as a Class C power amplifier Class C amplifier
is only suitable for use in communications applications, because it is a very high power amplifier distortion.
5, Class D amplifier, also known as class D amplifier
It amplifying transistor once opened i.e. directly to the load and the power supply is connected, current flows but transistors with voltage, so no power dissipation. When the output transistor is turned off, all of the power supply voltage appears on the transistor, but there is no current and therefore do not consume power so that the theoretical efficiency is one hundred percent.
Class D amplifier amplifying the advantage that the maximum efficiency, power supply can be reduced, almost no heat, so no large radiator, body size and significantly reduced weight, low-distortion theory, a good linearity. However, this amp work complexity, increase line itself would inevitably be biased, so very few truly successful product, the price is not cheap.
Third, by function
1. The preamplifier
also known as pre-preamplifier, amplifier before pre-amplification and a control section for enhancing the voltage amplitude of the signal, an input signal is selected, tone adjustment and volume control functions.
The power amplifier 2.
PA abbreviation amplifier for enhancing the signal power to drive the speaker sound of an electronic device. Without source selection, amplifier and so on.
3. The integrated amplifier
The pre-amplification and power amplification of two parts mounted amplifier in the same chassis called a combined amplifier, a common amplifier family are generally combined formula .
Fourth, by the use of sub-populations
1. Professional Amplifier
generally used for meetings, performances PA. Designed to output power, improve the circuit, good thermal protection based. When the amplifier, sound dry and hard Naiting.
civil power amplifier 2.
is divided ldquo; HI-FI amplifier rdquo; ldquo; AV amplifier rdquo; ldquo; KALAOK amplifier rdquo; and the variety of commonly used functions into one the so-called ldquo; integrated amplifier rdquo ;. ldquo; KALAOK amplifier rdquo; also a power amplifier developed in recent years. It is general that the difference amplifier ldquo; KALAOK amplifier rdquo; reverberation from the past to the present development of BBD analog reverberation of DIGETAL, tone, a microphone amplifier.
In recent years, some manufacturers to market demand, the combination of a variety of functions including AV amplifier, KALAOK integrated amplifier, including the so-called ldquo; rdquo ;, integrated amplifier This amplifier is a hodgepodge, everything do anything good, more practical and low-grade amplifier rural areas.
3. Special amplifier
refers to a power amplifier for use in special occasions, for example, alarms, vehicle low voltage amplifier and the like.
Fifth, use is divided into
1.AV amplifier
AV amplifier is specifically designed for home theater use amplifiers usually have four or more number of channels as well as surround sound decoding, and with a display screen. This class amplifier in order to create a real movie theater environment sound effects for the audience to experience the main purpose. And digital sound field circuit finishing touch, provide different effects for a variety of sound field program play.
However, since the AV amplifier circuit in the signal flowThe link, after too many and complex processing circuit, the purity of sound rdquo; has been too much ldquo; rdquo ;, so stained with a compatible AV amplifier HI-FI when replay is not ideal. Which is a lot HI-FI enthusiasts a reason to AV amplifier unworthy of care.
2.Hi-Fi amplifier
Hi-Fi amplifier for high fidelity reproduction of music true colors designed amplifier, typically two-channel design, and no display. Designed to ldquo; excellent sound amplifier US, high fidelity rdquo; for the purpose. Various high-tech embodied in such amplifiers. Prices ranging from one thousand to several hundred thousand dollars.
ldquo; HI-FI amplifier rdquo; divided ldquo; split rdquo ;, and ldquo; merger rdquo ;. Generally speaking, in the same grade ldquo models; split rdquo; ldquo higher signal to noise ratio on the index, the channel segmentation degree; combined machine rdquo ;. Tone and easily than through a signal line. The combined machine type, there are easy to use, relatively low cost.
2. Routine maintenance
1. Amplifier should be placed in a dry and ventilated place, avoiding moisture, high temperature, corrosive chemical fumes environment.
2. PA should avoid serious environmental electromagnetic interference, such as fluorescent ballasts aging electromagnetic interference radiation will cause the machine CPU program disorder, cause the machine does not work.
3. Amplifier should be placed in a safe, stable, easy to fall countertop or cabinet used to avoid collision damage or fell to the ground, the machine damage or disaster.