Introduction to Capacitors

Electronics 1CVHS

Terms

Capacitance - the ability to store energy in the form of an electric charge

Capacitor - a device designed to hold capacitance

Details Base Unit - Farad

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 Also have a working voltage rating

WVDC Similar to resistor power rating

Capacitors are not heat sensitive

How a Capacitor Works A capacitor is two conductors

(plates) separated by an insulator (dielectric)

A capacitor stores energy when it is connected to a voltage source (such as a battery).

Current flows until the capacitor becomes charged to the same voltage as the source.

Simple Capacitor

Discharging a Capacitor

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

Non-electrolytic capacitor

Electrolytic capacitor has polarity dielectric soaked in

electrolyte Never install backwards

Variable capacitor plate surface area can be

adjusted

Types of Capacitors Non-electrolytic

Ceramic Disc

Dipped Mica

Paper (molded)

Types of Capacitors Electrolytic

Axial Lead Radial Lead

Types of Capacitors 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 Capacitance vs. Capacitor Unit of Measure & Ratings How Does it Work? Working Considerations What affects Capacitance Three Types of Capacitors Capacitance Code