1. EEE340Lecture 131 3-8. Electric flux density and dielectric constant Where the electric flux density (displacement) Absolute permittivity Relative permittivity (dielectric constant) Electric susceptibility

2. EEE340Lecture 132 Example 3-12. Dielectric shell. Find and. Solution Make Gaussian surface r<r i r i <r<r o r>r o The electric flux Regardless of r  is in i or ii or iii However the E-field expressions are r r o r i <r<r o

3. EEE340Lecture 133 3-8.1: Dielectric strength Breakdown Transformer oil with air bubbles. Example 3-13 Two spherical conductors. Solution. a). From equal potential condition, or b2 b1

4. EEE340Lecture 134 That b) The electric field at the sphere surfaces:

5. EEE340Lecture 135 3-9. Boundary conditions for electrostatic fields The tangential component of the E-field is continuous across the boundary E 1t =E 2t Show. Apply In the integral form Where L is a narrow frame abcd. So that and

6. EEE340Lecture 136 The normal component of field is continuous across the interface, provided no surface charge exists. Show. Make a flat disk Gaussian surface Hence Special cases :

7. EEE340Lecture 137 Example. Given a charge-free flat dielectric interface separating  1 =5  o and  2 =2  o. If find Solution Using boundary conditions: Hence and z x E1E1 E2E2