Basic  Electricity  

EAS  199A  Lecture  Notes  

Learning  Objec:ves  

Successful  comple:on  of  this  module  will  enable  students  to  •  Link  the  basic  model  of  an  atom  to  the  flow  of  electricity  

•  Apply  the  defini:ons  of  Amp,  Volt,  Coulomb,  Joule,  WaJ  to  unit  conversions  and  basic  problems  involving  current  and  voltage  

•  Apply  Ohm’s  Law  to  simple  DC  circuits  

Defini:on  

Concise  Oxford  English  Dic:onary,  revised  10th  edi:on  

Electricity  is  a  form  of  energy  resul2ng  from  the  existence  of  charged  par2cles  (such  as  electrons  or  protons),  either  sta2cally  as  an  accumula2on  of  charge  or  dynamically  as  a  current.    

Defini:on  

Concise  Oxford  English  Dic:onary,  revised  10th  edi:on  

Electricity  is  a  form  of  energy  resul2ng  from  the  existence  of  charged  par2cles  (such  as  electrons  or  protons),  either  sta2cally  as  an  accumula2on  of  charge  or  dynamically  as  a  current.    

Defini:on  Conductor:    A  conductor  is  a  material  that  

readily  allows  the  flow  of  electricity.  A  good  conductor  has  a  high  numerical  value  of  a  conduc2vity,  and  a  low  numerical  value  of  resistance.  

Defini:on  Conduc+vity:    All  materials  have  a  measurable  

property  called  electrical  conduc:vity  that  indicates  the  ability  of  the  material  to  either  allow  or  impede  the  flow  of  electrons.  Materials  that  easily  conduct  electricity  have  a  high  conduc:vity.  

Defini:on  Insulator:    An  insulator  is  a  material  that  tends  

to  impede  the  flow  of  electricity.  A  resistor  has  a  low  numerical  value  of  conduc:vity  and  high  numerical  value  of  resistance.  

Defini:on  Semiconductor:    A  semiconductor  is  a  material  with  

conduc:vity  between  that  of  a  conductor  and  insulator.    The  conduc:vity  of  a  semiconductor  

can  be  changed  by  exposing  it  to  an  electrical  field,  light,  mechanical  pressure,  or  heat.  

Simplified  Func:onal  Differences  

Semiconductors  can  be  used  in  devices  that  act  like  a  switch.    

Elements  

•  Pure  substances  are  made  of  elements.  •  An  element  consists  of  atoms  •  Atoms  have  a  nucleus  consis:ng  of  protons  and  neutrons  

•  Electrons  move  in  shells  around                                                the  nucleus  

Elements  

•  Number  of  protons  determines  the  element  •  Number  of  electrons  varies  – State  of  electrical  charge  –  Is  the  element  in  a  chemical  bond?  

•  Number  of  neutrons  varies  with  isotope    

La-Lu57-71

Ac-Lr89-103

Tc

Lr

Pm

Np Pu Am Cm Bk Cf Es Fm Md No

BhRf Db Sg Hs Mt

1

2

3

4

5

6

7

1.00791 4.00262

20.1801014.0077

39.9481835.45317

18.998915.9998

83.79836

131.2954

(222)86

12.0116

C

10.811

B

5

26.982

Al

13 28.086

Si

14 30.974

P

15 32.065

S

16

6.941

Li

3 9.0122

Be

4

22.990

Na

11 24.305

Mg

12

39.098

K

19 40.078

Ca

20 44.956

Sc

21 47.867

Ti

22 50.942

V

23 51.996

Cr

24 54.938

Mn

25 55.845

Fe

26 58.933

Co

27 58.693

Ni

28 63.546

Cu

29 65.38

Zn

30 69.723

Ga

31 72.64

Ge

32 74.922

As

33 78.96

Se

34 79.90435

85.468

Rb

37 87.62

Sr

38 88.906

Y

39 91.224

Zr

40 92.906

Nb

41 95.96

Mo

42

132.91

Cs

55 137.33

Ba

56

138.91

La

57

178.49

Hf

72 180.95

Ta

73 183.84

W

74

(223)

Fr

87 (226)

Ra

88

(227)

Ac

89

(98)43 126.90

I

53101.07

Ru

44 102.91

Rh

45 106.42

Pd

46 107.87

Ag

47 112.41

Cd

48

186.21

Re

75 190.23

Os

76 192.22

Ir

77 195.08

Pt

78 196.97

Au

79 200.59

Hg

80 204.38

Tl

81 207.2

Pb

82 208.98

Bi

83 (209)

Po

84 (210)

At

85

114.82

In

49 118.71

Sn

50 121.76

Sb

51 127.60

Te

52

H He

NeN

ArCl

FO

Kr

Xe

Rn

Br

IA

IIA

IIIB IVB VB VIB VIIB IB IIB

IVA VA VIA VIIA

VIIIB

VIIIA1

54

2

3

13 14 15 16 17

18

6 7 8 9 10 11 12

IIIA

174.97

Lu

71140.12

Ce

58

232.04

Th

90 231.04

Pa

91 238.03

U

92

140.91

Pr

59 144.24

Nd

60

(262)103

(145)61

(237)93 (244)94 (243)95 (247)96 (247)97 (251)98 (252)99 (257)100 (258)101 (259)102

150.36

Sm

62 151.96

Eu

63 157.25

Gd

64 158.93

Tb

65 162.50

Dy

66 164.93

Ho

67 167.26

Er

68 168.93

Tm

69 173.05

Yb

70

(2 )72107(26 )7104 (26 )8105 (2 )71106 (277)108 (2 )76109 (2 1)8

Ds

110 (2 )80

Rg

111

Copyright Eni G© 2010 eneralic

10.811

B

5

13 IIIA

(2 )85

Cn

112

HYDROGEN HELIUM

NEONNITROGEN

ARGONCHLORINE

FLUORINEOXYGEN

KRYPTON

XENON

RADON

CARBONBORON

ALUMINIUM SILICON PHOSPHORUS SULPHUR

LITHIUM BERYLLIUM

SODIUM MAGNESIUM

POTASSIUM CALCIUM SCANDIUM TITANIUM VANADIUM CHROMIUM MANGANESE COBALT NICKEL COPPER ZINC GALLIUM GERMANIUM ARSENIC SELENIUM BROMINE

RUBIDIUM STRONTIUM YTTRIUM ZIRCONIUM NIOBIUM MOLYBDENUM

CAESIUM BARIUM

LANTHANUM

HAFNIUM TANTALUM TUNGSTEN

FRANCIUM RADIUM

ACTINIUM

TECHNETIUM IODINERUTHENIUM RHODIUM PALLADIUM SILVER CADMIUM

RHENIUM OSMIUM IRIDIUM PLATINUM GOLD THALLIUM LEAD BISMUTH POLONIUM ASTATINE

INDIUM TIN ANTIMONY TELLURIUM

PE

RIO

D

GROUP

IRON

MERCURY

LUTETIUMCERIUM

THORIUM PROTACTINIUM URANIUM

PRASEODYMIUM NEODYMIUM

LAWRENCIUM

PROMETHIUM

NEPTUNIUM PLUTONIUM AMERICIUM CURIUM BERKELIUM CALIFORNIUM EINSTEINIUM FERMIUM MENDELEVIUM NOBELIUM

SAMARIUM EUROPIUM GADOLINIUM TERBIUM DYSPROSIUM HOLMIUM ERBIUM THULIUM YTTERBIUM

BOHRIUMRUTHERFORDIUM DUBNIUM SEABORGIUM HASSIUM MEITNERIUM

BORON

ATOMIC NUMBER

ELEMENT NAME

SYMBOL

RELATIVE ATOMIC MASS (1)

GROUP NUMBERSCHEMICAL ABSTRACT SERVICE

(1986)

GROUP NUMBERSIUPAC RECOMMENDATION

(1985)

Lanthanide

ActinideROENTGENIUM

(1) Pure Appl. Chem., , No. , (200 )81 11 2131-2156 9

PERIODIC TABLE OF THE ELEMENTS

LANTHANIDE

ACTINIDE

DARMSTADTIUM

h .comttp://www.periodni

Relative atomic mass is shown with five

significant figures. For elements have no

stable nuclides, the value enclosed in brackets

indicates the mass number of the longest-lived

isotope of the element. However three such

elements (Th, Pa, and U) do have a

characteristic terrestrial isotopic composition,

and for these an atomic weight is tabulated.

COPERNICIUM

Periodic  Table:  Copper  

Bohr  Model  of  the  atom  (Cu)  

Electrical  current  in  a  trivial  circuit  

Battery+ –

Conductor

Electrical  current:  atomic  model  

Battery+ –

Electrical  Current:  electron  flow  

Battery+ –

Electrical  Current:  electron  flow  

Battery+ –

Electron flow:negative topositive

Electrical  Current:  current  conven:on  

Battery+ –

Electron flow:negative topositive

Current flow:positive tonegative

How  many  electrons?  

How  many  electrons?  

Electrical  current:  poten:al  

Electrical  current:  electron  flow  

Electrical  current:  conven:on  

Defini:on:  Charge  

Elementary  charge  1  electron  =  1.602    ×  10–19  coulomb  

Coulomb  1  coulomb=  6.24    ×  1018  electrons  

Defini:on:  Current  

!

1A = 1Cs

1 C = 6.24 "1018electrons

Defini:on:  Voltage  

!

1V = 1 Jcoulomb

Voltage  and  electrical  work  

A Be–

If  the  voltage  between  A  and  B  is  one  volt,  then  one  Joule  of  work  is  done  when  6.28  ×  1018  electrons  move  from  A  to  B.  

Ohm’s  Law  

V

I

R V = IR

Ohm’s  Law  

Ohm’s  Law  

Ohm’s  Law  

Ohm’s  Law  

Example:  Current  through  a  light  bulb  

A  1.5  volt  AA  baJery  is  wired  to  a  light  bulb  with  a  resistance  of  30  Ω.  a.  Sketch  the  components.  b.  Draw  the  circuit.  c.  Find  the  current  flowing  through  the  light  

bulb.  

Example:  Current  through  a  light  bulb  

A  1.5  volt  AA  baJery  is  wired  to  a  light  bulb  with  a  resistance  of  30  Ω.  a.  Sketch  the  components.    

Example:  Current  through  a  light  bulb  

A  1.5  volt  AA  baJery  is  wired  to  a  light  bulb  with  a  resistance  of  30  Ω.  a.  Sketch  the  components.  b.  Draw  the  circuit.      

Apply  Ohm’s  Law  to  the  loop      V  =  I  R  

V  and  R  and  known,  so  solve  for  I        I  =  V/R      

Subs:tute  the  known  values  and  compute  the  value  of  I          

 where  1  A  =  1000  mA.    

Example:  Current  through  a  light  bulb  

c.  Find  the  current  flowing  through  the  bulb      

I = 1.5V30!

= 0.05 A = 50 mA