Ultrasonic Motor (Piezo Sonic Motor)
                    Ultrasonic motors are quiet, high-torque motors driven by piezoelectric ceramics that expand and contract when voltage is applied.
Unlike a motor that uses general electromagnetic force, it operates using frictional force without using coils or magnets, so it is a compact and lightweight motor that can be used in a magnetic field environment and has no backlash.
                    
                        
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