With the development of modern science and technology, computer equipment is also developing rapidly. Today, the CPU ( Central Processing Unit ) in the computer can already exceed 1g MHz.Various graphics accelerator cards enable computer enthusiasts to enjoy more realistic 3D images. The chips in these devices have very strict temperature requirements and may burn down if they are not taken care of. Therefore, heat sinks or fans are usually added to these chips.

However, since the equipment in the computer is generally placed in the computer case, in order to protect it from external factors, the case is generally tightly sealed, which makes it difficult to reduce the temperature in the case. When the temperature in the whole cabinet is high, it will affect the operation of computer equipment, especially in hot summer weather. In view of this situation, some computer manufacturers have installed a cooling fan in the computer case, and its rotation speed is fixed and will not change with the change of temperature, i.e.the purpose of regulating and controlling the temperature cannot be achieved, so that the temperature in the case is in an unstable state.

A computer case cooling fan technical scheme:the fan is connected in a temperature control circuit.   With this device, the voltage at both ends of the fan will be controlled by the temperature control circuit and the input voltage of the fan will be automatically adjusted according to the temperature in the cabinet, so as to adjust the rotation speed of the fan and keep the temperature in the cabinet in a relatively stable state.