Hair dryers, electric drills, and battery-powered toy cars as microphones and loudspeakers

摘要

An erm is induced in a conductor moving in a magnetic field; a current-carrying conductor placed in a magnetic field experiences a force, causing it to move. These principles are at work in generators, where mechanical energy is transformed into electrical energy, and in motors, where electrical energy is transformed into mechanical energy. And the same principles apply to loudspeakers, in which electrical energy is transformed into mechanical energy, and to microphones, where mechanical energy is transformed into electrical energy