ELECTRICITY PPTCOMPILED & EDITED BY

MUKESH KUMAR CHHIPA

TGT WE K V 2 AJMER (RAJ.)

9269048633(M)

Electricity TheoryVIR PIV and Capacitors!!!

Energy When an object is at

some height in a gravitational field it is said to have gravitational potential energy, PEg

PEg

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 energy into electrical energy

BatteryCarbon Electrode

Zinc Electrode

Sulfuric Acid

+

Capacitor A capacitor is a storehouse of charge and energy 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 energy in the form of electrically separated charges

Capacitance is the ratio of charge to potential difference

QC

V

unit Farad, F

C1F=1

V

Charge Movement

Charge Movement

Circuit Analogy

Types of Current AC Alternating current charges

continuously change direction forward and 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

VR

I

2

unit ohm,

V Js1 1 1

A C

Ohm’s Law

V IR

Resistance Depends on: Length, cross sectional area,

material, and temperature

LR

A

2

resistivity, m

L length, m

A cross sectional area, m

Resistance and Temp

Resistance and 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 energy is transformed Electric Power: The rate at which charge

carriers convert PEE into non-mechanical energy

P IVunit watt, W

J1 W = 1

s

Reading and 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 – 5

p 615 1 – 6; p 616 2-4, 7,9

p 621 1 – 5

Extra Practicep 626 – 628 11, 20 – 54