1. Basic Theory of Circuits, SJTU Chapter 6 Capacitors and Inductors

2. Basic Theory of Circuits, SJTU Capacitors A typical capacitor A capacitor consists of two conducting plates separated by an insulator (or dielectric). C: capacitance Unit: farad(F)

3. Basic Theory of Circuits, SJTU Values: picofarad (pF) -- microfarad (mF) Polyester Mica Electrolytic Ceramic Types: fixed variable Circuit symbols for capacitors a) fixed capacitor b) variable capacitor

4. Basic Theory of Circuits, SJTU VAR of Capacitor Passive sign convention A capacitor is an open circuit to dc The voltage on the capacitor cannot change abruptly (in condition that i is limited)

5. Basic Theory of Circuits, SJTU Stored Energy in Capacitor Is capacitor active? equivalent circuit for the parallel capacitors

6. Basic Theory of Circuits, SJTU Equivalent circuit for the series capacitors

7. Basic Theory of Circuits, SJTU Inductors An inductor consists of a coil of conducting wire. Typical form of an inductor L: inductance Unit: henry (H)

8. Basic Theory of Circuits, SJTU Circuit symbols for inductors Values: microhenrys(  H)--- tens of henrys(H) Types: Fixed variable Iron, steel Plastic, air

9. Basic Theory of Circuits, SJTU VAR of Inductor What happens when the current is constant? Integrating form: An inductor acts like a short circuit to dc. The current through an inductor cannot change abruptly (in condition that v is limited).

10. Basic Theory of Circuits, SJTU Stored Energy in Inductor Is inductor active? Equivalent circuit for the series inductors

11. Basic Theory of Circuits, SJTU Equivalent circuit for the parallel inductors