Computer host automatic temperature control circuit

When the computer is running large-scale software or games,
the heat inside the computer will increase, causing the internal temperature to rise, especially in
hot summer. Although the CPU and graphics card fans are installed inside the machine
, the hot air has poor circulation and
cannot be discharged outside the machine in time, causing the temperature inside the machine to be relatively high. In order to solve this problem, the automatic temperature control circuit
of the computer host as shown in the figure can freely set the temperature control point. When the temperature inside the machine is higher than the set temperature, the suction and exhaust fans run at the same time to discharge the hot air inside the machine in time. At the same time, it sucks in the cold air outside the machine to circulate the air inside the machine, thereby achieving the purpose of cooling.     RT, R, and the four-voltage comparator LM339 form a temperature detection circuit. RT is a positive temperature coefficient thermistor. First, place RT in hot water of 40 ~ 45℃, carefully adjust RP until the fan rotates exactly; the adjustment is completed Finally, install the entire circuit board in a suitable place in the chassis. The power supply is directly connected to the +12V power supply of the computer . One of the fans M1 and M2 is used as an exhaust fan and the other is used as a suction fan. They are installed in empty positions in the chassis as Exhaust fan and intake fan.     The function of the heart is to produce a certain hysteresis in the output.