I need to control a DC motor with an Arduino. The motor needs approximately 9-12V and 200mA (700mA peak current). I use a 9V battery or a power supply, a transistor (BD135) and a 250 Ohm as base resistor. The following diagram illustrates the circuit - note that R2 is the DC motor and the flyback diode is missing in the diagram, but I used one:
The Problem: I need to be able to stop the motor much more faster than with setting. I read about shorting out the motor's wires or even to turn the motor in the other direction. I've found an explanation, how to control the direction of the motor using 4 diodes and two transistors, but I'm unsure how to try shorting out the motor's wires.
Can I really just connect the two motor wires to a second transistor to stop the motor? How much current/voltage will flow through this transistor?