8015 four line cooling fans

Size: 80 x8015mm

Double ball bearing:

Voltage: 12 v

Current: 0.26 A

Speed: 1200 ~ 3500 RMP full speed is 1200 RPM

Air volume: 39.2 CFM

Noise: 18 to 39 dba (MAX)

Interface: the mainboard 4 p

Support: PWM intelligent temperature control, speed

Line length: 10 cm

Applicable: the case of cooling, cooling transformation of CPU, and other cooling purposes

PWM features dual ball bearing sanyo precision long life stability; First class materials and workmanship; Using PWM intelligent temperature control technology, according to the mainboard to detect CPU temperature and automatically adjust the rotate speed, the temperature under normal circumstances, quiet state is low speed, because when the CPU load suddenly increases with temperature rise to the moment when the fan is at the same time improve the speed to achieve the bulk temperature, when the heat dissipation and timely return to normal after cooling and low speed state of quiet. The PWM fan speed control make fan runtime minimum noise, energy saving, and can prolong the life of the fan, is a kind of perfect cooling technology. The key of knowledge

The principle of PWM intelligent temperature control fan

1. The PWM technology background

PWM (Pulse Width Modulation), Intel to radiator evaluation standard is very strict. The traditional temperature control fan is the use of fan bearing temperature measuring probe detects the fan air inlet temperature near, thus to adjust the speed of the fan. Although the temperature control to solve the certain problem, but there is a rough precision, and the temperature control of variable speed can only do the low-speed poles.

PWM is short for pulse width modulation circuit, in industrial control, have already widely used on the microcontroller. And Intel will he and combining the motherboard CPU temperature detection, apply it to the radiator fan speed precision control, achieved good effect.

2. The functions and features of PWM intelligent temperature control fan

First of all, the PWM regulating fan speed fan is directly from the CPU temperature information, without any temperature measurement device on the fan. According to the different CPU temperature, temperature control fan will have different speed adjustment and the matching, and fan speed change can do 4 class five, or even more, basically is the feeling of CVT. Because it is real-time adjustment of pulse width signal fan speed change is very sensitive, rotation speed and the change of the CPU temperature is almost synchronization.

Second, the PWM fan in the computer on standby, you can keep on a very low speed. In standby time, CPU temperature below 40 to 50 degrees, its speed is one thousand turn around, only greatly reduces the operating noise. Designed for the highest speed, more than two thousand turn, only in the CPU temperature is close to the limit temperature, which is 65-65 degrees, going to happen. Compared with the traditional temperature control fan has a larger scope of speed control, better solved the problem of the noise and performance.

Third, PWM control fan at the instant of the boot, speed will be promoted to the highest, for several seconds, down to the level of low speed on standby. This feature is also the most obvious characteristics of PWM intelligent temperature control fan, which can be used to determine fan and the motherboard is true with PWM function, or its function if there is a failure, and even can be used as a true and false box package reference criterion of radiator.

3. The simple principle of PWM intelligent temperature control fan

On the motherboard with PWM functions, in addition to the original temperature measurement circuit, a PWM control chip, his role is according to the measured temperature of the CPU temperature detection circuit, a different duty ratio of PWM pulse signal. The pulse is a kind of square wave, in a cycle, the square wave signal is the high level of time accounts for the proportion of the whole cycle, we call the duty ratio. Whole cycle is high level signal, the duty ratio is 100%, whereas duty ratio is zero. The most simple PWM control circuit, the fan on the circuit board of a control circuit, we make it simple to understand for a triode, which level and PWM square wave pulse connection, this level if there is a high level, the triode additional poles in a conducting state, if it is a low level, in addition the poles in the off state. If a square wave pulse signal of the duty ratio is 50%, namely high level signal accounts for half the time of one cycle, then the triode in a cycle is half the time in the conduction state. Through this transistor in a cycle of conduction time length, it is easy to realize to the fan speed control. If the PWM square wave pulse signal of the duty ratio can be a variety of levels, so the speed of the fan can do a variety of levels.