How is the energy transferred from the source to the load in

How is the energy transferred from the source to the load in any electromagnetic circuit? A microphone consists of a flat attached to a coil of wire, and the coil is immersed in a stationary magnetic field. When sound hits the plate, it forces the plate and coil of wire to move back and forth proportional t the sound amplitude. Briefly identify and explain a principle we\'ve discussed in class that allows that microphone to produce an electrical signal representation of the sound.

Solution

1. Energy transfer in electromagnetic circuits occurs by way of coupling, or by way of some wireless power transmitter, say an antenna. While an electric charge is associated with an electric field, a current carrying wire is associated with a magnetic field. While both have energies, both being static cannot propagate. Witht time varying fields, they can propagate power, and thus they function. There are various types of electromagnetic energy transfer, by way of near field or far field communication. That in turn again depends on the Drange and the lambda in use.

2. Principle similar to that of a DC generator. According to Faraday’s laws of electromagnetic induction, whenever a conductor is placed in a varying magnetic field (OR a conductor is moved in a magnetic field), an emf (electromotive force) gets induced in the conductor. The magnitude of induced emf can be calculated from the emf equation of dc generator. If the conductor is provided with the closed path, the induced current will circulate within the path. In a DC generator, field coils produce an electromagnetic field and the armature conductors are rotated into the field. Thus, an electromagnetically induced emf is generated in the armature conductors. The direction of induced current is given by Fleming’s right hand rule. This is another such principle wherein motion incites electrical signal.