1. ELECTROMAGNETIS M LECTURE#09 Instructor: Muhammad Mateen Yaqoob

2. Parallel Plate Capacitors  A careful inspection of electric field lines for a parallel-plate capacitor reveals that field is uniform in the central region between the plates.  However, the field is non-uniform at the edges of the plates. Mateen Yaqoob Department of Computer Science

3. Combinations of Capacitors  Two or more capacitors often are combined in electric circuits.  We can calculate the equivalent capacitance of certain combinations using methods. Mateen Yaqoob Department of Computer Science

4. Parallel Combination Mateen Yaqoob Department of Computer Science

5. Parallel Combination  Rule: Voltage (V) across any electric circuit element remains same in parallel circuit and Current (I) remains same in series circuit  Total charge on capacitors connected in parallel is the sum of the charges on the individual capacitors. Because the voltages across the capacitors are the same, the charges that they carry are; Mateen Yaqoob Department of Computer Science

6. Series Combination Mateen Yaqoob Department of Computer Science

7. Problem: Series and Parallel Combination Mateen Yaqoob Department of Computer Science

8. Energy Stored in a Charged Capacitor  Suppose that q is the charge on the capacitor at some instant during the charging process. Mateen Yaqoob Department of Computer Science

9. Capacitors with Dielectrics  A dielectric is a non-conducting material, such as rubber, glass, or waxed paper. When a dielectric is inserted between the plates of a capacitor, the capacitance increases.  If the dielectric completely fills the space between the plates, the capacitance increases by a dimensionless factor K, which is called the dielectric constant of the material. Mateen Yaqoob Department of Computer Science

10. Capacitors with Dielectrics Mateen Yaqoob Department of Computer Science

11. Capacitors with Dielectrics Mateen Yaqoob Department of Computer Science