Electrical Engineering ⇒ Topic : Composite Medium

Composite Medium

If V is the total p.d., we can write

               figure (a)

                                      .............. (1)

Suppose the space between the plates is occupied by three dielectrics of thicknesses d₁, d₂ and d₃ metres and relative permittivities ε_r1, ε_r2 and ε_r3 respectively as shown in Figure (A). The electric flux density D in the dielectrics remains the *same and is equal to Q/A. However, the electric intensities in the three dielectrics will be different and are given by

If V is the total p.d. across the capacitor and V₁, V₂ and V₃ the p.d.s. across the three dielectrics respectively, then,

                            V = 

                                         FIGURE (A)

But Q/V is the capacitance C of the capacitor

In general,