In which type of system are DC motors commonly used?

DC motors are commonly used in low power and portable applications due to their ability to provide precise control of speed and torque, as well as their relatively simple design and lower cost. These motors are ideal for applications where size and weight are significant factors. For example, they can be found in small appliances, battery-powered tools, and toys, where the need for lightweight and easily controllable operation is paramount.

In contrast, high voltage transmission systems typically utilize alternating current (AC) for efficiency and long-distance transmission. Data communication systems do not require the mechanical output provided by DC motors, focusing instead on signal processing. Large-scale power generation generally involves AC generation due to its advantages in efficiency and the ability to easily transform voltage levels for transmission. Thus, the use of DC motors in low power and portable applications aligns perfectly with their characteristics and advantages.