TRANSFORMERS AND COILS

Coils are another important component in any analog circuit and extensively used in power electronics. In a ordinary circuit due to its inductance it oppose the change of current flow in the line which it is connected. A magnetic flux is stored in coil which decay with time and stored energy is released.  A filter circuit include a coil and resistance which separate high or low frequency signal and thus demodulation circuit need coil. A speaker have coil which vibrate when current flow in it as current cause magnetic field opposite to a strong permanent magnet and thus sound occur on the spider or paper cone.