Pages 454–455, Problems 8.9, 8.10, D8.13, D8.14, D8.15.

8.9 A stepper motor has 24 North teeth and 24 South teeth. What angle change occurs on each step? If a full step is output every 1 ms (and assuming it doesn’t slip), at what speed does the motor spin?
The shaftwill rotate 360°/(4 · n) per step.
360 / (4 * 24) = 3.75 degrees of change occurs on each step.
If a stepper motor with 50 teeth North and South has 200 spr then 24 teeth should be about 100 spr.
Rps = 4f/N = 4 * 1MHz / 100 = 40000 rps.

8.10 Draw a figure similar to Figure 8.80 showing how half stepping works.
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D8.13 Design an interface for a ±24 V, 500 mA geared DC motor. The time constant of the motor is 10 ms. Include software to adjust the delivered power from 0 to 100%.

D8.14 Design an interface for a ±12 V, 500 mA bipolar stepper motor. There are 200 steps/revolution. Write software to spin the motor at 1 rps.

D8.15 An alarm is powered by 120 VAC, and the on/off state of the alarm is controlled by an EM relay. Design the interface between a computer output port and the EM relay. The dropout voltage is 3.5 V, and the coil current needs at least 100 mA. Limit the coil voltage to 6 V. Write three software functions: Alarm_Init, Alarm_On, and