Teori ElektrisitasVIR PIV dan Kapasitor!!!

Energi When an object is at

some height in a gravitational field it is said to have gravitational energi potensial, PEg

PEg

Energi Like gravitational fields causing masses to

have energi potensial, Electric Fields cause charges to have electric energi potensial, PEE

PEE is a type of mechanical energi MEtotal = KE + PEg + PEs + PEE

Energi To give something PE you must do work

(apply force over a distance) on the something (raising up in g-field)

For PEE to occur a FE must be applied by either

a. An E-Field (uniform)b. A pair of charges

EnergiUniform E-field

AB

Line Color

Red: E-Field

Black: Equipotential lines

Blue: charge displacement

E

W PE FdF EqPE qEd

Energi Pair of Charges

1 22

1 2

c

E c

W PE Fdq qF kr

q qPE kr

Electric Potential

Any point in an electric field is said to have Electric Potential, V. However, only a Difference in PE is measurable (remember zero point) so we talk of electric potential difference AKA potential difference, ΔV.

EPEVq

PEVq

unit Volt, VJ1V=1C

Potential Difference

Potential Difference

Potential Difference Back to the zero point

A convenient zero point to chose in a circuit or any electric system is the “ground”

Battery (cells) A battery produces

electricity by transforming chemical energi into electrical energi

BatteryCarbon Electrode

Zinc Electrode

Sulfuric Acid

+

Capacitor A capacitor is a storehouse of charge dan energi that

can be reclaimed when needed for a specific application

A capacitor will only charge to the potential difference between the terminals of the battery

Capacitance Capacitance, C: The ability of a conductor to

store energi in the form of electrically separated charges

Capacitance is the ratio of charge to potential difference

QCV

unit Farad, FC1F=1V

Capacitance Capacitance depends on size dan shape

0ACd

2

-120 2permittivity of free space, 8.85x10

Area of one plated distance between plates

CNm

A

Capacitor Energi stored in a

capacitor

21 12 2

U energy QV CV

Electric Current Movement of electric charge Rate of charge movement

QIt

unit Ampere, AC1A=1s

Charge Movement

Charge Movement

Circuit Analogy

Types of Current AC Alternating current charges

continuously change direction forward dan back at 60 Hz

Example: outlets (approx 120 V) DC Direct current charges move in one

direction Example: batteries

AC-DC Debate births the Electric Chair

Resistance Resistance is the impedance of the motion of

charge through a conductor The ratio of potential difference across a

conductor to the current it carries

VRI

2

unit ohm, V Js1 1 1A C

Ohm’s Law

V IR

Resistance Depends on: Length, cross sectional area,

material, dan temperature

LRA

2

resistivity, mL length, m

A cross sectional area, m

Resistance dan Temp

Resistance dan Thickness

Resistor An electronic element

that provides a specified resistance.

A current or voltage REGULATOR

Power (it’s Electric!) Power: Rate at which work is done. OR Rate

at which energi is transformed Electric Power: The rate at which charge

carriers convert PEE into non-mechanical energi

P IVunit watt, W

J1 W = 1 s

Reading dan Homework Read Chapter 17

pp 593 - 625

HW due on test day:p 599 1-3; p 601 2, 3, 5-9;p 607 1 – 4 (B); p609 1 – 5p 615 1 – 6; p 616 2-4, 7,9p 621 1 – 5

Extra Practicep 626 – 628 11, 20 – 54