DC motor

A DC motor turns direct current into rotation using a clever mechanical switch. Picture a loop of wire sitting between two magnets: push current through it and the loop feels a force that flips it a half-turn — but then it would just stop, balanced. The DC motor solves this with a commutator, a split ring with carbon brushes that reverses the current direction every half-turn, so the loop always feels a push in the same rotational sense and keeps spinning.

Its great charm is simplicity: connect it to a battery and it runs, and its speed is nearly proportional to voltage while its torque is nearly proportional to current, making it beautifully easy to control. The price is the brushes — they wear out, spark, and create electrical noise, which is why the brushless motor was invented to do the same job with electronics replacing the mechanical switch. A toy car, a car window winder, and an old cordless drill are all classic brushed DC motors.