Receiver principle
The general receiver is the use of electromagnetic inductive principle at work, or in a coil placed on permanent magnetic field in electrical signal to sound, the interaction force of a coil, rely on the force to drive the cone vibration sound receiver. The coil, placed in a permanent magnetic field, is called the voice coil".
There is also a high voltage electrostatic receiver, it is through between the two conductive film close coupled with high voice signal, the two conductive film because of the electric force and vibration, to push the air around the vibration, so as to sound. The receiver now used more and more in the mobile phone.