 Transducers such as loudspeakers and microphones convert between electrical current and mechanical force to reproduce signals such as speech.When compared with common internal combustion engines (ICEs), electric motors are lightweight, physically smaller, provide more power output, are mechanically simpler and cheaper to build, while providing instant and consistent torque at any speed, with more responsiveness, higher overall efficiency and lower heat generation.However, electric motors are not as convenient or common as ICEs in mobile applications (i.e.