speed sensory circuit based on the infrared device and the
ripple component of the motor current, respectively. The
electric sprayer will be applied to a direct voltage source 15 V,
12 V, and 10 V [5]. According to the working principle of DC
motor, the speed of DC motor is proportional to the applied
voltage value under the same mechanical load condition.
Therefore, the measured DC motor will be driven to work at
three different speeds.