Distinguish by interface
There are many different kinds of cooling fans, so according to the interface, they can be divided into 2-pin, 3-pin and 4-pin, or 2pin/3pin/4pin.
2pin electric fan
The 2pin electric fan is very simple. There are only two red and black wires, one connected to power and the other grounded. The structure is very simple, so there is no function. Of course, there are fans with a large 4pin interface, but this kind of fan is actually a 2-pin fan, such as Baodikai. DC fan. This type of electric fan does not have a variable speed function. The interface is 12V power supply. The large 4pin interface is used for greater power, so the speed is naturally fast, but the noise is relatively large. Since there is no variable speed capability, the fan will always Furiously, regardless of whether the CPU is hot or not. Don't choose this if you like to install it yourself.
3pin electric fan
It is precisely because the 2pin fan can’t adjust the speed, so there is a 3pin fan. Because we are using the computer, the CPU does not always work at full capacity, so if the fan works at full speed, it will cause two problems. , First, the CPU does not generate much heat, the fan does not need to rotate so fast, which wastes electricity, and the second is that the CPU will produce a lot of noise when working at full speed. The 3pin electric fan adds a yellow wire on the basis of the red and black wires. The main function of the yellow wire is to measure the speed. With the yellow wire, the motherboard can monitor the working condition of the electric fan, but the 3pin electric fan is also lacking because it uses voltage regulation. To change the speed, this adjustment method is not flexible. First, the CPU temperature detection is done by the motherboard, and the temperature information reflected by the motherboard must be wrong. Second, the motherboard needs to set many parameters, but some motherboards do not support it. There are so many fan settings, so players need to understand the specific BIOS functions of the motherboard when buying the motherboard. In addition, the starting voltage is different for different electric fans. Perhaps after the main board drops the voltage, the A fan can reduce the speed, but the B fan directly stops.
4pin electric fan
Since the 3pin electric fan did not solve the problem of fan speed adjustment, Intel and other manufacturers later introduced a new speed regulation specification, which was upgraded from 3pin to 4pin. The extra line is called the PWM line, which is the pulse width adjustment. change. The color of the line is generally black, yellow, green, blue, or black, red, yellow, and blue. The common point is that blue is the PWM line and black is the ground line. The voltage of the 4pin electric fan is constant, and the fan speed is adjusted through the PWM mechanism. The PWM pulse signal can output different duty cycles, so that different fan speeds can be adjusted according to practical needs, which is more accurate and flexible, and the PWM mechanism of the fan does not need to rely on the motherboard BIOS (not relying on the motherboard), now there are categories of PWM, vulgar PWM and high-speed PWM, in general, the overall performance of high-speed PWM is the best.
matters needing attention
Even if you buy a fan with a 4pin interface, pay attention to whether the motherboard is controlled by PWM. Some 4pin electric fans still cannot be adjusted after being connected to the motherboard, then the problem is the motherboard's problem. When buying a motherboard, you should be optimistic about the manual or know the relevant parameters of the motherboard in advance. When it comes to NC/VCC, it does not support PWM speed control. Now it is the best choice to choose a 4pin electric fan that supports PWM speed regulation and PWM function.
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