With the progress of the times, the development of science, the popularization of computers, people's pursuit of "light, thin, and short" functions of computers, and the comfort of use is another indispensable condition. Among the eight major problems of PC appearance, structure, transmission, power distribution, environment, electromagnetic interference, heat transfer, and noise, heat transfer and noise play an important role.
The computing speed of the PC is accelerated, the heat is constantly rising, and the cooling modules are gradually increasing. How to "dissipate heat" is a topic that everyone is currently thinking about. In addition to the requirements for heat transfer, noise is also one of the important choices for using products. People don't want to buy PCs that make a lot of noise, and the biggest source of that annoying noise is the AC fan .
AC cooling micro fans are difficult to take care of cooling without making annoying noises. When applying a fan, it is necessary to consider the rotation speed and noise of the AC cooling fan , which is a headache for designers. The higher the fan speed, the greater the flow and static pressure, and the greater the relative noise, but the speed is insufficient, and it cannot provide enough air volume and static pressure to take away heat. In this case, the variable fan came into being. When a large amount of heat needs to be taken away, the rotation speed is high, and when a large amount of heat is not required to be taken away, it can be operated at a low speed. When the PC generates a lot of heat, high-speed air volume and air pressure are required to take away the heat, and of course the noise is also loud; when the AC cooling fan does not need to run at high speed, the speed can be reduced to reduce the noise.
Generally, a DC fan needs at least one set of DC power supply plus one signal line or PWM control signal line. The FG signal is a signal generated inside the fan to indicate the speed of the fan. A general fan consists of a 4-stage motor, so the AC cooling fan rotates. There will be two sets of identical signals in a circle.