Can you read circuit ?
Its totally going out of my head. M a computer science student and i dont have much idea abt circuit.
Click on the circuit picture to see it all !
There are TWO OPTIONS just for you..
Both options switch the Arduino low Vcc voltage to the 12v or 7v or whatever Fan voltage you want to run.
The top is the relay option
The bottom is a simple transistor option
The left is the arduino symbolically represented by brain neurons, and needs a +Vcc and a Ground to think => your program Mr Computer Science Student.. To raise and lower output lines to activate the relay or the transistor to start or stop your fan (represented by the black square with five 5 blades).
he should drive the relay with a transistor too
Right you are.
Here is the wiring which makes the simple transistor version even more desirable.
Again click the image to see it all.
Click on the circuit to see it all !
It shows two options
Top is a 5v or 3.3v relay depending on the Arduino represented by the brain neurons on the left. The relay closes 12v power or7v or whatever fan voltage you want to your fan. When the output pin is low the relay closes, when the output pin is high the relay turns the fan off.
Bottom is a simple mosfet transistor, less wiring to turn your fan ON & off
Your question was answered in your previous question.