1. Chapter 11
Capacitance

2. Objectives After completing this chapter, you will be able to:
Explain the principles of capacitance
Identify the basic units of capacitance
Identify different types of capacitors
Determine total capacitance in series and parallel circuits
Explain RC time constants and how they relate to capacitance

3. Capacitance Capacitance Capacitor
Ability to store electrical energy in an electrostatic field
Basic unit is the farad (F)
Represented by letter C
Capacitor
Possesses a specific amount of capacitance
Either fixed or variable

4. Capacitance (cont’d.)
Figure A capacitor consists of two plates (conductors)
separated by a dielectric (insulator or nonconductor).

5. Capacitors Factors that affect capacitance Area of the plate
Distance between the plates
Type of dielectric material
Temperature

6. Figure 11-3. Electrolytic capacitors.

7. Capacitors (cont’d.)
Figure Paper and plastic capacitors.

8. Capacitors (cont’d.)
Figure Ceramic disk capacitors.

9. Capacitors (cont’d.)
Figure Variable capacitors.

10. Capacitors (cont’d.) Total capacitance in series circuits:
Total capacitance in parallel circuits:

11. RC Time Constants
Figure Circuit used to determine RC time constant.

12. RC Time Constants (cont’d.)
RC circuit time constant formula:
t = RC
where: t = time in seconds
R = resistance in ohms
C = capacitance in farads

13. RC Time Constants (cont’d.)
Figure Chart of time constants required to charge and discharge a capacitor.

14. Summary
Capacitance (C) allows for the storage of energy in an electrostatic field
The unit of capacitance is the farad (F)
Capacitor types include: electrolytic, paper, plastic, ceramic, and variable
Total capacitance in series circuits:

15. Summary (cont’d.) Total capacitance in parallel circuits:
RC circuit time constant formula:
t = RC
It takes five constants to fully charge and discharge a capacitor