How to Build a Simple DC Fan Circuit

DC fan



In this project, we will demonstrate how to build a simple DC Fan circuit.

An DC fan is a fan which is run on DC power.

An AC fan differs in that it is run on AC power.

When sufficient DC voltage is fed into the terminals of the fan, the fan spins.

Power, in the form of DC voltage, is all that is needed to get a DC fan to operate and spin.

To power a DC fan, we feed the fan its rated voltage.

For example, to power a 12VDC fan, we need to feed it 12 volts DC.

This power can come from any DC voltage source, such as a DC power supply or even batteries. If using batteries, in order to get 12V output, you would have to place 8 'AA' batteries in series. This is because each 'AA' battery gives 1.5V. Being that in series they add, 1.5V * 8= 12V. However, being that 8 batteries represent a lot of batteries, usually this will not be done, and a DC power supply will be used.

So all we would need to do is take the DC power supply and adjust it so that it gives out 12V output or a little higher. Then takes the probes of the DC power supply and connect them to the terminal wires of the fan. The positive terminal wire of the fan must match up with the positive terminal wire of the power supply. And the negative terminal wire of the fan must match up with the negative terminal wire of the power supply. Polarity must be consistent between the two.

Once this is in place, this is all that is needed for the fan to work.

All the fan needs is the 12 volts of DC voltage, if it is rated for 12V. With this power, it can run.


Parts Needed

  • 9 or 12VDC DC Fan
  • DC Power Supply
  • Batteries (Optional Replacement)
  • Alligator Clips


The above parts are the only necessary items needed to create this simple DC fan circuit.

If you can find a fan which is rated for 9VDC, this is even better, because then you can use a single 9-volt battery in order to supply adequate power to turn on and operate the fan and do away with the DC power supply, if you do not have one. 9VDC fans are rarer, but they can still be found. An example of one can be found at Allelectronics- 9VDC Fan. 12VDC are much more common and can be found at the same site and many others.

You can use alligator clips or whatever connect you have in order to connect the DC power supply to the terminal wires of the fan.

Below is the complete circuit with the DC power supply and fan together:

DC fan circuit

This is the most basic DC fan circuit that can be produced.

We can do a number of modifications to give this fan more features, such as add a potentiometer to the circuit. With a variable resistor, we can vary the resistance of the circuit. This, in turn, varies the voltage which is fed to the fan. With more voltage, the fan runs quicker, because it's fed more power. With lower voltage, the fan speed runs slower, because it's fed less power. This is a common feature on most fans- the ability to vary the speed by changing the resistance of the circuit.

We can also add a simple SPST switch, so that we can turn the power to the fan on or off.

Basically, we can add a lot of features to this, but this project shows the simplicity of an simple DC fan circuit.

Related Resources

How to Build an AC Fan Circuit



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