For the recommended transistor, currents up to 1 A can be controlled. If you need more current, see Chapter 3 for directions on how to select a more powerful transistor.
A translator or microcontroller must be used to produce the sequence of pulses according the position or the speed needed in your applications. Remember that the power transistors must be mounted on heat sinks.
Figure 1 - Driving a stepper motor with Darlington NPN transistors.