ok
everything is working fine with the 3904 !

(i burned up 3 of those, , but got one running in the SAME breadboard)

i cant tell you the motor ratings because im using an rc car(the chasis and the motors, after ripping the circuitry apart )

but i guess the TIP122 is rated much more than my motor.

ok, i used a 3904

the transistor got too hot and burnt my finger .
is it because im not using a resistor?

it was even smoking

and the funny thing is, the motor stopped with TIP122(that means everything worked), for sometime, but i dunno what happened; after a while, it was back to the same problem .

thank you will try that

btw , can you tell me why the diode is placed parallel to the motor?
i mean, wouldnt it be better if it had been placed, on the outout pin?

i have the 2N3904

will that do?

i dont think theres any prob with the transistor (the motor SLOWS down and speeds up)

but the motor doesnt STOP
even if i take the base pin out, the motor continues to run , but slowly

i think i means there is little current still going through the transistor
i tried using 3 TIP122 transistors, same results.

http://bildr.org/2011/03/high-power-control-with-arduino-and-tip120/

its the same schematic and same code

but i have not used any resistor, nor the dioide(in the motor)

instead of TIP120 , i used TIP122

also, can u tell me why it doesnt even slow down with the TIP127?
i'm running a 9 v motor , with aprroz 9.6 v batteries

i connected an rc car which runs on 9.6 v batteries to just ONE of the motors(back wheels)

the problem is, when the battery is fully charged , the transistor passes too much current, and the motor coninues to run even at analogWrite(pin,0)

how can i understand what type of transistor to use to power a 9 volt motor with the 5v arduino ?