the electronic drive as shown in Figure 2.4 is used which is originally
developed by Guy Marsden in [11]. From Figure 2.4, the output voltage of the sensor
drives the input of a low-cost MIC502 fan-management chip, which produces a pulsewidth
modulated signal to a motor drive chip. From this point, it is summarized that
PWM technique can be applied in the study to adjust the average current in the coil,
which controls the magnetic field to suspend the object. This average current magnetic