Transcript Introduction to Capacitors - Conestoga Valley Blog Site

Introduction to Capacitors
Electronics 1
CVHS
Terms
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Capacitance - the ability to store energy in the
form of an electric charge
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Capacitor - a device designed to hold
capacitance
Details
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Base Unit - Farad
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Also have a working voltage rating
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Typically measured in micro-farads
Symbol: F (1/1,000,000th of a Farad)
Also can be in pico-Farads (1/1,000,000,000,000) of a
Farad
WVDC
Similar to resistor power rating
Capacitors are not heat sensitive
How a Capacitor Works
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A capacitor is two conductors
(plates) separated by an insulator
(dielectric)
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A capacitor stores energy when it
is connected to a voltage source
(such as a battery).
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Current flows until the capacitor
becomes charged to the same
voltage as the source.
Simple Capacitor
Discharging a Capacitor
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Capacitor has the ability to discharge
immediately
Battery discharges over time
Short leads of capacitors before working with
them
Use a resistor to slowly discharge a capacitor so
it is not damaged
Danger of Electrical Shock
Factors Affecting Capacitance
 Plate area
 Distance
between plates
 Dielectric material
Schematic Symbols
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Non-electrolytic
capacitor
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Electrolytic capacitor
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has polarity
dielectric soaked in
electrolyte
Never install backwards
Variable capacitor
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plate surface area can be
adjusted
Types of Capacitors
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Non-electrolytic
 Ceramic Disc
 Dipped
Mica
 Paper (molded)
Types of Capacitors
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Electrolytic
 Radial Lead
 Axial Lead
Types of Capacitors
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Variable
Capacitance Code
NOTE: Value is in pico-farads!
Practice
First Digit
Second Digit
Third Digit
Letter
1
0
4
K
100,000 pF or .1 µF ± 10%
5
8
2
F
5,800 pF or .0058 µF ± 1%
2
4
3
G
24,000 pF or .024 µF ± 2%
Review
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Capacitance vs. Capacitor
Unit of Measure & Ratings
How Does it Work?
Working Considerations
What affects Capacitance
Three Types of Capacitors
Capacitance Code