Hi there, I have what seems to be a simple project, but I can't get it to work. I have 12V fans hat will be powered every x hours for x minutes. The fans have only 2 pins and the project is being powered with an external power supply. The code itself should be pretty straight forward const int TR…

[image] Calado: 12V- to Drain FAN- to Source Wrong way around! Also you do not mention a flyback diode. Without this, you are playing Russian roulette. A resistor (e.g. ~330R) between the Arduino pin and the Gate, and a 10K pulldown on the Arduino pin is also wise.

Please grab pen and paper and make schematics showing the fan driver. That transistor is good.

The diode must be able to take the motor current during flyback. If you have an avalanche rated MOSFET this diode will not be needed as the MOSFET will conduct at a lower voltage. Check the MOSFET data this information is now appearing on many of them.

Thanks for your replies, I got it working without a hiccup. My only question resides with the flyback diode. I researched what it does and it's pretty simple to understand it's function, but where does it go? Can I just solder it to the fan leads, stripe to + and the other side to -? That's what I …

I usually solder the diode and cap (if used) right to the motor terminals along with the power wires as you describe. Diode band to motor + and other end to motor -.

It will not do anything if there is no inductance in the circuit. However if there is an inductor when you apply power it charges up forming a magnetic field. When you disconnect the power the inductor needs to discharge. To do this the polarity reverses and the voltage rises (no limit) until it is …

Controlling 2-pin 12V fans intermittently

Projects General Guidance

groundFungus May 13, 2023, 8:34pm 4

MOSFET motor driver. MOSFET and motor power supply must be able to handle motor stall current.

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Controlling 2-pin 12V fans intermittently

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