Let's Make Robots!

current limiting

Turning on a motor using a transistor (question)

I'm building a fire-fighting robot for a science expo and everything is fine so far (at least the electronic part is!) but I`m stuck with the fan motor. I`ve already fried a N3906 (don`t know what I expected).

RepRap Stepper Driver v1.2 and Next Gen CNC

In the picture from top-left, clockwise to bottom-left: the terminal block (24V power up to 13A), the 2 X-axis drivers, the Y-axis driver (blue heat sink), and the Z-axis driver (blue heat sink), the Arduino controller (direction x3/enable x3/step x3), and just below the terminal block there is a small 9V regulator board to shift 24V down to 9V for the Arduino.  Everything is mounted on an MDF board, and the board is mounted with baling wire.