Summary

We have investigated the behavior of dielectric materials in alternating electric fields. We see that for ideal dielectrics, the current leads the voltage by 90° and power dissipation is equal to zero. On the other hand, in real dielectrics, the current leads voltage by an angle 90° - δ where δ is the loss angle. This results in real and imaginary parts of the dielectric constant and the ratio of imaginary to real part is loss tangent, depicting the power loss in a real dielectric.