BASIC ELECTRICITY

CHAPTER 1

ATOMIC STRUCTURE

TERMS TO KNOW

ALTERNATING CURRENT(AC)

ATOM ATTRACTION CENTRIFUGAL FORCE CONDUCTORS DIRECT CURRENT (DC) ELECTRON ELECTRON ORBITS

INSULATORS MATTER NEGATIVE NEUTRON NUCLEUS POSITIVE PROTON SEMICONDUCTORS VALENCE ELECTRONS

HISTORY OF ELECTRICITY GREEKS DISCOVERED 2500 YEARS AGO USED PRACTICALLY ABOUT 100 YEARS AMBER BECAME CHARGED WHEN

RUBBED WITH OTHER MATERIALS: ATTRACTED THINGS LIKE LEAVES, FEATHERS, BITS OF CLOTH

THE WORD ELECTRIC COMES FROM THE WORD “ELEKTRON”

LIST A: POSITIVE

LIST B: NEGATIVE

STUDY OF ATOMS ATOM IS THE BUILDING BLOCK OF

UNIVERSE ALL MATTER IS MADE FROM A

COMBINATION OF ATOMS MATTER IS ANY SUBSTANCE THAT HAS

MASS AND TAKES UP SPACE MATTER CAN EXIST IN THREE FORMS:

SOLID, LIQUID, OR GAS ELEMENT: CAN’T BE DIVIDED INTO A

SIMPLER SUBSTANCE

STUDY OF ATOMS

THREE STATES OF WATER

THREE PARTS OF AN ATOM: 1.ELECTRON

2. PROTON 3.NEUTRON

NUCLEUS: PROTON AND NEUTRON

NOTICE THE CHARGES OF EACH PART

PROTON=POSITIVE CHARGE

ELECTRON=NEGATIVE

CHARGE

LAW OF CHARGES….

Opposite charges attract and like charges repel

VALENCE ELECTRONS

OUTER SHELL OF ATOM IS KNOWN AS “VALENCE SHELL”

ELECTRONS LOCATED IN OUTER SHELL ARE “VALENCE ELECTRONS”

THE VALENCE SHELL CAN’T HOLD MORE THAN 8 ELECTRONS

COPPER: GOOD CONDUCTOR BECAUSE OF ONLY ONE VALENCE ELECTRON

CURRENT FLOW HAPPENS WHEN ELECTRONS MOVE FROM

ATOM TO ATOM.

INSULATORS: HAVE 7 OR 8 ELECTRONS IN VALENCE SHELL

SEMICONDUCTORS: HAVE 4 ELECRONS IN VALENCE SHELL

CONDUCTORS

THEY HAVE ONLY 1 OR 2 VALENCE ELECTRONS:

THEY GIVE UP THOSE ELECTRONS EASILY WITH LITTLE EFFORT

THEY ALLOW CURRENT FLOW EASILY: LOW RESISTANCE!!!!!!

EXAMPLES OF GOODCONDUCTORS SILVER: 1 VALENCE ELECTRON COPPER: 1 VALENCE ELECTRON GOLD: 1 VALENCE ELECTRON ALUMINUM: 3 VALENCE ELECTRON PLATINUM: 1 VALENCE ELECTRON

INSULATORS

MATERIALS THAT HAVE 7 OR 8 VALENCE ELECTRONS

RESIST FLOW OF ELECTRICITY ELECTRONS ARE HELD TIGHTLY

AND ARE NOT GIVEN UP EASILY

EXAMPLES OF INSULATORS

RUBBER PLASTIC GLASS WOOD

SEMICONDUCTORS

MATERIALS THAT HAVE 4 VALENCE ELECTRONS

ARE NEITHER GOOD FOR CONDUCTORS OR INSULATORS

USED TO MAKE DIODES AND TRANSISTORS

COMPUTORSCOMPUTORS ARE FULL OF SEMICONDUCTOR MATERIAL

SILICON AND GERMANIUM MOST COMMON USED

METHODS OF PRODUCINGELECTRICITY

MAGNETISM=GENERATOR CHEMICAL=BATTERY PRESSURE=PIEZO SENSORS HEAT=THERMOCOUPLES FRICTION=STATIC LIGHT=PHOTO ELECTRIC

REVIEW…..

OPEN THE BOOKS TO SUMMARY AT END OF CHAPTER.

DO THE REVIEW QUESTIONS IN CLASS.