Input/Output Devices 49 Supply voltage +12 V 15 Trigger 3 Rotation 2 Set 14 4 13 6 8 Brown Black Green Yellow Red SAA1027 5 12 9 11 Red Stepper motor with its four stator coils Figure 2.39: Driver circuit connections with the integrated circuit SAA1027. 2.3 Examples of Applications The following are some examples of control systems designed to illustrate the use of a range of input and output devices.