CAPACITANCE
DC Circuits
Example:
Find the time constant of a 100 µF capacitor in series with a 100W resistor
(Figure 20).
Figure 20 Example - Capacitive Time Constant
TC
RC
TC
(100W)(100µF)
TC
0.01 seconds
Summary
The important information on capacitors is summarized below.
Capacitance Summary
A capacitor is constructed of two conductors (plates) separated by a dielectric.
A capacitor will store energy in the form of an electric field caused by the
attraction of the positively-charged particles in one plate to the negatively-
charged particles in the other plate.
The attraction of charges in the opposite plates of a capacitor opposes a
change in voltage across the capacitor.
Capacitors in series are combined like resistors in parallel.
Capacitors in parallel are combined like resistors in series.
The capacitive time constant is the time required for the capacitor to charge
(or discharge) to 63.2 percent of its fully charged voltage.
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