Temperature controlled DC Fan



 With this simple circuit you are able to control the speed of a DC fan according to temperature measured by a temp sensor. It’s an ideal addon for your PC cooling fans to eliminate produced noise.

On the first site two circuits are displayed. The first circuit is a simple version using LM317 and a temperature depended resistor to detect temperature. The voltage applyed to the fan is proportional to temperature. The second is a more advanced one using LM35 as temp sensor and four OPAMPs to achieve linear response of the output according to temperature measured.

On the second site you can find a Temperature controlled 12V dc Fan circuit using a Thermistor. All designs are selected for their simpicity, so the choise is yours!

Temperature controlled DC Fan – [Link]

Temperature-controlled 12V dc Fan – [Link]

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