[Help] Newbie making an arduino-controlled motor

So I recently started playing with the arduino(uno) and decided to try and connect some motors together.
I have a 30N06L transistor and a 12v dc motor. I found this diagram that shows how to connect them:


I noticed they use a capacitor for each motor. My question is, is that necessary? Will I fry or damage my Arduino in any way if I don't use one? or is it there just to catch noise?

Thanks

Those are diodes, not capacitors. They're connected back-to-front to prevent spikes casued by the motor stopping from zapping the transistor.

So yep they're basically compulsory- use them whenever you have a motor, a solenoid or a relay driven like that.

Oh ok, thanks. How about this diagram (going from + to - on the motor)? Is this also a diode or is it a capacitor?

We connected it without one and it worked fine.

Is this also a diode or is it a capacitor?

We connected it without one and it worked fine.

It's a diode too... have a look at a site like this to help you with identification and purpose of components.

The motor will run without the diode, but don't leave it out unless you're happy to fry the transistor when the motor stops and sends a spike back.