Figure 1 Stepper motor shield using PNP transistors.
Each winding is on when the input of the corresponding transistor is set to the low logic level. The circuit must be connected to a sequencer or other circuit to give the desired sequence of pulses to make the motor run or to put it in a predetermined position. Using the recommended transistors, the block can drive motors with up to 1 A from TTL or CMOS logic. See Chapter 3 if you want to use more powerful transistors.