Loop as a magnetic dipole and electric motor

A current loop in a magnetic field experiences a torque: it behaves like a small magnet, a magnetic dipole. From this the electric motor is born. This section builds the magnetic moment $\vec{\mu} = iA\,\hat{n}$, the torque and energy of the dipole, how the motor works with the commutator, and the energy balance with the back electromotive force, closing with the solenoid.

• Magnetic moment of a loop
• Torque and energy of a magnetic dipole
• The electric motor
• The commutator
• Back electromotive force and energy balance
• The solenoid