1. Capacitors
2 conducting plates separated by an insulator (or dielectric)
Connect to a voltage source, stores +q and –q on plates:
q = Cv
C = capacitance in F
Symbol

2. Differentiate:
Integrate:
For DC signals, a capacitor is an open circuit.
Power:
Energy:
Continuity of Energy: Voltage of a capacitor cannot “jump.”
Ideal vs. Real Capacitors:

3. Example 1. Find the current through a 200-μF capacitor whose voltage is shown.

4. Example 2. Find the stored energy in each capacitor under dc conditions.
Ans. 16 mJ, 128 mJ

5. Parallel Capacitors

6. Series Capacitors

7. Example 3. Find the voltage across each capacitor.
Ans: 15V, 10V, 5 V

8. Inductors
a coil of conducting wire
L = inductance in H
Symbol

9. v-i char::
Integrate:
For DC signals, an inductor is a short circuit.
Power:
Energy:
Continuity of Energy: Current in an inductor cannot “jump.”
Ideal vs. practical Inductors:

10. Example 4. Under dc conditions, find iL and vC and stored energy.
Ans. 2A, 10V,4J, 50J

11. Series and Parallel Inductors
Inductors: L behaves like R
Capacitors: C behaves like G
Voltage and Current Divider Equations apply.

12. Example 5. Given:
Find:

13. Passive Elements: Power and Energy

14. Compare with Mechanics
Mass:
Spring:
Fluid Friction:

15. Electrical Mechanical Rotational q x θ i u ω v f τ C k κr R D Dr L M
J (or I)