Unit One:Unit One:Quantities, Units, andQuantities, Units, and

Electrical SafetyElectrical Safety

John ElberfeldJohn Elberfeld

JElberfeld@itt-tech.edu

WWW.J-Elberfeld.comWWW.J-Elberfeld.com

1ET115 DC Electronics

DC ElectronicsDC Electronics

• In this course you will concentrate In this course you will concentrate on controlling direct current using on controlling direct current using resistorsresistors

• You will be using Digital Multimeters, You will be using Digital Multimeters, power supplies, and resistors in power supplies, and resistors in most of your labsmost of your labs

22

Computer Simulations Computer Simulations

• You will also use a computer You will also use a computer program called MultiSim to build and program called MultiSim to build and test models of circuits in your labstest models of circuits in your labs

33

Course Objectives - ICourse Objectives - I

1. Perform conversions and calculations on 1. Perform conversions and calculations on electrical units of measure using metric electrical units of measure using metric prefixes, scientific notation, and prefixes, scientific notation, and engineering notation.engineering notation.

2. Explain standard electrical safety 2. Explain standard electrical safety procedures.procedures.

3. Explain the Bohr model for atomic 3. Explain the Bohr model for atomic structure and how it relates to electrical structure and how it relates to electrical concepts such as insulators and concepts such as insulators and conductors including solids, liquids, and conductors including solids, liquids, and gases.gases.

44

Course Objectives - IICourse Objectives - II4. Identify electronic schematic symbols 4. Identify electronic schematic symbols

related to DC circuits.related to DC circuits.5. Describe how to use components and 5. Describe how to use components and

sources such as resistors, rheostats,sources such as resistors, rheostats,potentiometers, switches, batteries, and potentiometers, switches, batteries, and

power supplies.power supplies.6. Explain what resistance is and its 6. Explain what resistance is and its

importance in electrical circuitsimportance in electrical circuits7. Apply Ohm’s Law and Watt’s Law to basic 7. Apply Ohm’s Law and Watt’s Law to basic

DC circuits.DC circuits.

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Course Objectives - IIICourse Objectives - III8. Analyze series, parallel, and series-8. Analyze series, parallel, and series-

parallel circuits.parallel circuits.9. Apply Kirchhoff’s voltage and current 9. Apply Kirchhoff’s voltage and current

laws to analyze DC circuits.laws to analyze DC circuits.10. Apply voltage and current division rules 10. Apply voltage and current division rules

to DC circuits.to DC circuits.11. Calculate the effect of a load on a 11. Calculate the effect of a load on a

voltage-divider.voltage-divider.12. Applying Thevenin’s theorem to simplify 12. Applying Thevenin’s theorem to simplify

network circuits.network circuits.13. Explain the maximum power transfer 13. Explain the maximum power transfer

theorem.theorem.

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Course Objectives - IVCourse Objectives - IV14. Analyze circuit operation with multiple 14. Analyze circuit operation with multiple

voltage sources using the superposition voltage sources using the superposition theorem.theorem.

15. Describe principles of operation for 15. Describe principles of operation for magnetic devices.magnetic devices.

16. Use proper prototype board wiring and 16. Use proper prototype board wiring and test procedures for DC resistive circuit test procedures for DC resistive circuit components including using the digital components including using the digital multimeter.multimeter.

17. Simulate and test DC circuits using 17. Simulate and test DC circuits using Multisim.Multisim.

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ClassesClasses• Classroom: Theory Room #_____Classroom: Theory Room #_____

• Class day and time: ______________Class day and time: ______________

• Lab Room: Lab #_______Lab Room: Lab #_______

• Lab day and time: ________________Lab day and time: ________________

• Bring to every class:Bring to every class:– TextbookTextbook– Calculator with Engineering ModeCalculator with Engineering Mode– Lab suppliesLab supplies– Paper, pencil, etcPaper, pencil, etc

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ScheduleSchedule• Expect to be in lab and class - working the Expect to be in lab and class - working the

full timefull time• 11 class meetings11 class meetings

– Review quiz every weekReview quiz every week– Unit tests weeks 5 and 8 Unit tests weeks 5 and 8 – Week 11 Lab and Theory FINALWeek 11 Lab and Theory FINAL

• If you miss more than 21 calendar days in If you miss more than 21 calendar days in a row you may be dropped from the class a row you may be dropped from the class according to the school/financial aid according to the school/financial aid regulations regulations

99

Requirements/ExpectationsRequirements/Expectations• Come to class on time – Come to class on time –

EVERY CLASS!EVERY CLASS!• Turn in your assignments when dueTurn in your assignments when due

– Points may be subtracted on Points may be subtracted on unexcused, late assignmentsunexcused, late assignments

• Participate in classParticipate in class• Email me BEFORE class if you must Email me BEFORE class if you must

be absentbe absent• Plan on 3-5 hours of homeworkPlan on 3-5 hours of homework• every week – sometimes more!every week – sometimes more!

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Use Common SenseUse Common Sense• Come to class on time, prepared to work Come to class on time, prepared to work

until the end of classuntil the end of class• Be courteous, respectful, honest, and Be courteous, respectful, honest, and

helpful to your classmates and the helpful to your classmates and the instructorinstructor

• Avoid distracting other students during Avoid distracting other students during class (no cell phones, class (no cell phones, use laptops ONLY for class use laptops ONLY for class projects, eat quietly and projects, eat quietly and clean up afterwards, clean up afterwards, no chatting, etc.)no chatting, etc.)

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EvaluationEvaluation• Lab Exercises.............................30% Lab Exercises.............................30%

• Assignments...............................25% Assignments...............................25%

• Quizzes…………………..............10% Quizzes…………………..............10%

• Unit Exams.................................10%Unit Exams.................................10%

• Theory Final............................... 15% Theory Final............................... 15%

• Lab Final.....................….............10%Lab Final.....................….............10%

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QuizzesQuizzes• There are NO surprise quizzes – you There are NO surprise quizzes – you

willwill have a quiz or exam every week have a quiz or exam every week

• Quizzes will be similar to your Quizzes will be similar to your homework, which is similar to your homework, which is similar to your exams and the finalexams and the final

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HomeworkHomework• Homework is assigned each weekHomework is assigned each week

• Homework is due the next weekHomework is due the next week– Sometimes a quiz on the homework will Sometimes a quiz on the homework will

be used as a grade instead of grading be used as a grade instead of grading your homework papersyour homework papers

• ““Reasonable” teamwork and Reasonable” teamwork and cooperation on homework is cooperation on homework is acceptableacceptable– Copying is NOT acceptableCopying is NOT acceptable

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Unit ExamsUnit Exams• Unit tests will be given weeks 5 and 8 Unit tests will be given weeks 5 and 8

and can include questions on all and can include questions on all material covered to that pointmaterial covered to that point

• Schedule of exams subject to Schedule of exams subject to revisionrevision

• ITT requires these exams,ITT requires these exams,which are created by ITTwhich are created by ITT

1515 10%

Lab ExercisesLab Exercises• These have the BIGGEST effect on These have the BIGGEST effect on

your gradeyour grade

• Labs will be done each weekLabs will be done each week

• Cooperation and teamwork in lab are Cooperation and teamwork in lab are encouraged – copying is forbiddenencouraged – copying is forbidden

• Labs must be completed before you Labs must be completed before you leaveleave

1616 30%

Lab FinalLab Final• On Week 11, you will do a lab, and a On Week 11, you will do a lab, and a

write up, which will be gradedwrite up, which will be graded

• Grade is based on the help received Grade is based on the help received to complete the lab, and accuracy of to complete the lab, and accuracy of your workyour work

1717 10%

Theory FinalTheory Final• The Final exam will be given Week 11The Final exam will be given Week 11

• The exam is created by ITT and is The exam is created by ITT and is standard for the coursestandard for the course– 45 multiple choice questions worth 2 45 multiple choice questions worth 2

points off for each one wrongpoints off for each one wrong

1818 15%

ProgressProgress• You can check with me for your You can check with me for your

current grade in classcurrent grade in class• If you are in danger of failing, you If you are in danger of failing, you

will be officially notified as soon as will be officially notified as soon as possiblepossible

• Because we have only 10 classes Because we have only 10 classes where you will learn new material, where you will learn new material, missing just one class can set you missing just one class can set you behind – class attendance is the behind – class attendance is the most important thing you can do!most important thing you can do!

1919

ScheduleSchedule

Unit Unit Topic Topic Chpt LabsChpt Labs1.1. Quantities, Units, SafetyQuantities, Units, Safety 11 2 (#6-11)2 (#6-11)2.2. Voltage, Current, ResistanceVoltage, Current, Resistance 22 3 + 163 + 163.3. Ohm’s LawOhm’s Law 33 554.4. Energy and PowerEnergy and Power 33 66

5.5. Series CircuitsSeries Circuits Exam IExam I 44 77

6.6. Parallel CircuitsParallel Circuits 55 99

7.7. Series-Parallel CircuitsSeries-Parallel Circuits 66 1010

8.8. Thevenin’s, Power Thevenin’s, Power Exam 2Exam 2 66 1919

9.9. Superposition Theorem Superposition Theorem 66 1111

10.10. Magnetism & Magnetic DevicesMagnetism & Magnetic Devices 77 Lab Final Lab Final 11.11. Course Review and Course Review and Final ExamFinal Exam

2020

Unit One Objectives - IUnit One Objectives - I• Use scientific and engineering notation Use scientific and engineering notation

to represent quantities.to represent quantities.• Perform arithmetic calculations using Perform arithmetic calculations using

powers of ten.powers of ten.• Express electrical quantities with metric Express electrical quantities with metric

prefixes.prefixes.• Convert among engineering metric Convert among engineering metric

prefixes (pico, nano, micro, milli, kilo,prefixes (pico, nano, micro, milli, kilo,• mega).mega).• Express measured data with the proper Express measured data with the proper

number of significant figures.number of significant figures.• Define accuracy, error, and precision.Define accuracy, error, and precision.• Round numbers properly.Round numbers properly.

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Unit One Objectives - IIUnit One Objectives - II• Recognize electrical hazards.Recognize electrical hazards.• Describe causes of electrical shock.Describe causes of electrical shock.• Discuss the effect of current on the human Discuss the effect of current on the human

body.body.• List safety precautions to be observed List safety precautions to be observed

when working with electricity.when working with electricity.• Describe how Ground Fault Circuit Describe how Ground Fault Circuit

Interpreter (GFCI) works.Interpreter (GFCI) works.• Use a digital multimeter (DMM) to measure Use a digital multimeter (DMM) to measure

a predetermined low voltage on a power a predetermined low voltage on a power supply.supply.

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Reading AssignmentReading Assignment• Read and study Read and study

• Chapter 1: Quantities and Units Chapter 1: Quantities and Units Pages 1-16Pages 1-16

• Utility Voltages – Appendix DUtility Voltages – Appendix DPages 323-324Pages 323-324

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Lab AssignmentLab Assignment

• Experiment 1, Tables 1-5, 1-6, Experiment 1, Tables 1-5, 1-6, 1-7, and Review Questions Page 101-7, and Review Questions Page 10

• (Most of this will be done IN CLASS (Most of this will be done IN CLASS rather than in the lab)rather than in the lab)

• Rip out pages 3-10, staple them Rip out pages 3-10, staple them together, put yourtogether, put your NAME NAME on the on the pages, and turn them in before you pages, and turn them in before you leave the lableave the lab

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Written AssignmentsWritten Assignments• Do all the problems on the Do all the problems on the

homework handouthomework handout

• Be prepared for a quiz on questions Be prepared for a quiz on questions similar to those on the homework.similar to those on the homework.

• If there are any calculations, you If there are any calculations, you must show ALL your work for credit:must show ALL your work for credit:– Write down the formulaWrite down the formula– Show numbers in the formulaShow numbers in the formula– Circle answer with the proper unitsCircle answer with the proper units

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Large and Small NumbersLarge and Small Numbers• In electricity, you will work with very In electricity, you will work with very

large and very small numberslarge and very small numbers• You must use You must use engineeringengineering notation in notation in

your work and in your answersyour work and in your answers

• 736 400 = 736.4 x 10736 400 = 736.4 x 1033

• Like scientific notation, but the Like scientific notation, but the exponent is always a power of three (3)exponent is always a power of three (3)– Let’s start by reviewing scientific notationLet’s start by reviewing scientific notation

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Scientific Notation Scientific Notation • The value is expressed as a number The value is expressed as a number

between 1 and 10 which is then between 1 and 10 which is then multiplied by a power of 10multiplied by a power of 10

Powers of 10Powers of 10

• 101000 = 1 = 1

• 101011 = 10 = 10

• 101022 = 10 x 10 = 100 = 10 x 10 = 100

• 101033 = 10 x 10 x 10 = 1,000 = 10 x 10 x 10 = 1,000

• 101044 = 10 x 10 x 10 x 10 = 10,000 = 10 x 10 x 10 x 10 = 10,000

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Negative Powers of 10Negative Powers of 102828

-1

-2

-3

-4

110 =

101 1

10 = =10x10 100

1 110 = =

10x10x10 1,000

1 110 = =

10x10x10x10 10,000

Convert to Scientific NotationConvert to Scientific Notation

• Usually you will use your calculator, Usually you will use your calculator, but you need to understand the but you need to understand the processprocess

• Multiply by a useful value of 1Multiply by a useful value of 1• Choose a fraction that moves the Choose a fraction that moves the

decimal so only one digit remains to decimal so only one digit remains to the the leftleft of the decimal point of the decimal point

• Because you are multiplying a Because you are multiplying a number by 1, you are not changing its number by 1, you are not changing its value, only its appearancevalue, only its appearance

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Scientific NotationScientific Notation

• If you move the decimal point in the number to the If you move the decimal point in the number to the left, you are making the number smaller.left, you are making the number smaller.

• To keep the same value, you must multiply by a To keep the same value, you must multiply by a balancing power of 10balancing power of 10

1

2

3

10 6161•1=61• = •10=6.1•10

10 10100 612

612•1=612• = •100=6.12•10100 100

1000 61236123•1=6123• = •1000=6.123•10

1000 1000

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Negative Powers of 10Negative Powers of 10

-1

-2

-3

10 10.61•1=.61• =.61•10• =6.1•10

10 10100 1

0.061•1=.061• =.061•100• =6.1•10100 100

1000 10.0061•1=.0061• =.0061•1000• =6.1•10

1000 1000

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• If you move the decimal point in the number to the If you move the decimal point in the number to the right, you are making the number bigger.right, you are making the number bigger.

• To keep the same value, you must multiply by a To keep the same value, you must multiply by a negative power of 10negative power of 10

Use Your CalculatorUse Your Calculator• Your calculator can do all Your calculator can do all

of this for youof this for you

• On a Casio 115-ESOn a Casio 115-ES

• Do SHIFT-MODE-2 to shift the Do SHIFT-MODE-2 to shift the calculator into Line Input/Outputcalculator into Line Input/Output

• Do SHIFT-MODE-7 to shift the Do SHIFT-MODE-7 to shift the calculator into Scientific Notationcalculator into Scientific Notation

• Press 9 for the maximum number of Press 9 for the maximum number of digits availabledigits available

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Other CalculatorsOther Calculators• On some IT calculators, On some IT calculators,

NORM SCI ENG sets the NORM SCI ENG sets the notation mode. notation mode.

• Numeric notation modes affect only Numeric notation modes affect only the display of results, and not the the display of results, and not the accuracy of the values stored in the accuracy of the values stored in the unit, which remain maximal.unit, which remain maximal.

• NORM displays results with digits to NORM displays results with digits to the left and right of the decimal, as in the left and right of the decimal, as in 123456.78.123456.78.

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Calculator ManualCalculator Manual• SCI expresses numbers with one SCI expresses numbers with one

digit to the left of the decimal and the digit to the left of the decimal and the appropriate power of 10, as in appropriate power of 10, as in 1.2345678x101.2345678x1055 (which is the same as (which is the same as 123456.78).123456.78).

• ENG displays results as a number ENG displays results as a number from 1 to 999 times 10 to an integer from 1 to 999 times 10 to an integer power. The integer power is always a power. The integer power is always a multiple of 3.multiple of 3.

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Learn YOUR Calculator – Learn YOUR Calculator – and Use It!and Use It!

• You must be confident with your own You must be confident with your own calculatorcalculator

• Download the manual and learn how Download the manual and learn how to switch from normal (fixed) to to switch from normal (fixed) to scientific notation to engineeringscientific notation to engineering

• Once you figure it out, write it down Once you figure it out, write it down so you can look it up again later onso you can look it up again later on

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ExamplesExamples• Express 0.000 026 in scientific Express 0.000 026 in scientific

notation. (the space has no meaning)notation. (the space has no meaning)

• Set your calculator in Scientific Set your calculator in Scientific Notation modeNotation mode

• Enter .000 026 Enter .000 026

• Press the [=] keyPress the [=] key

• The display MAY be 2.6 x 10The display MAY be 2.6 x 10-5-5

• What does your display show? Is it What does your display show? Is it correct?correct?

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Table 1-5, Column 1, Page 8Table 1-5, Column 1, Page 8NumberNumber Scientific NotationScientific Notation

0.0829 V0.0829 V

48,000 Hz48,000 Hz

2,200,000 2,200,000 ΩΩ

0.000 015 A0.000 015 A

7,500 W7,500 W

0.000 000 033 F0.000 000 033 F

270,000 270,000 ΩΩ

0.000 010 H0.000 010 H

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Engineering NotationEngineering Notation

• Write the number using powers of Write the number using powers of ten.ten.

• Move the decimal point left while Move the decimal point left while increasing the exponent or right increasing the exponent or right while decreasing the exponent.while decreasing the exponent.

• The final exponent must be zero or a The final exponent must be zero or a number that is evenly divisible by number that is evenly divisible by three.three.

• The number itself must be greater The number itself must be greater than one and less than 1000than one and less than 1000

Use Your ENG buttonUse Your ENG button• Most calculators have an ENG button or Most calculators have an ENG button or

mode that automatically switches the mode that automatically switches the displayed answer to Engineering mode displayed answer to Engineering mode – USE IT!– USE IT!

• 47,000,000 = 4.7 x 1047,000,000 = 4.7 x 1077 (Scientific Notation) (Scientific Notation) = 47 x 10 = 47 x 1066 (Engineering Notation) (Engineering Notation)

• 0.000 027 = 2.7 x 100.000 027 = 2.7 x 10-5-5 (Scientific Notation) (Scientific Notation) = 27 x 10 = 27 x 10-6-6 (Engineering Notation) (Engineering Notation)

• 0.605 = 6.05 x 100.605 = 6.05 x 10-1-1 (Scientific Notation) (Scientific Notation) = 605 x 10 = 605 x 10-3-3 (Engineering Notation) (Engineering Notation)

3939

Table 1-5, Column 2, Page 8Table 1-5, Column 2, Page 8NumberNumber Engineering NotationEngineering Notation

0.0829 V0.0829 V

48,000 Hz48,000 Hz

2,200,000 2,200,000 ΩΩ

0.000 015 A0.000 015 A

7,500 W7,500 W

0.000 000 033 F0.000 000 033 F

270,000 270,000 ΩΩ

0.000 010 H0.000 010 H

4040

Reversing the ProcessReversing the Process• Example: Express 2.5 x 10Example: Express 2.5 x 10-6-6 in in

regular decimal form regular decimal form

• Set you calculator for Fixed or Set you calculator for Fixed or Normal displayNormal display

• Enter 2.5 [x10Enter 2.5 [x10xx] [ (-) ] 6 [=]] [ (-) ] 6 [=]

• [x10[x10xx] might be [EE] or [EXP]] might be [EE] or [EXP]

• Your result should be:Your result should be:

• 0.000 002 50.000 002 5

4141

TI DetailsTI Details• Numbers in scientific Numbers in scientific

notation can be entered in a notation can be entered in a scientific calculator using the scientific calculator using the EEEE key. key.

• Most scientific calculators Most scientific calculators can be placed in a mode that can be placed in a mode that will automatically convert any will automatically convert any decimal number entered into decimal number entered into scientific notation or scientific notation or engineering notation. engineering notation.

4242

Practice NowPractice NowNumberNumber Regular Decimal FormRegular Decimal Form

8.29 x 108.29 x 10-2-2

48.0 x 1048.0 x 1033

2.2 x 102.2 x 1066

15 x 1015 x 10-6-6

7.5 x 107.5 x 1033

3.3 x 103.3 x 10-8-8

2.7 x 102.7 x 1055

1.0 x 101.0 x 10-5-5

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Calculations with ExponentsCalculations with Exponents• When multiplying, you add exponentsWhen multiplying, you add exponents• (10x10x10)x(10x10) = 10x10x10x10x10 =10(10x10x10)x(10x10) = 10x10x10x10x10 =1055

• 101033 x 10 x 1022 = 10 = 103+23+2 = 10 = 1055

• 6 x 106 x 1055 x 2 x 10 x 2 x 1022 = 12 x 10 = 12 x 1077 = 120x10 = 120x1066

• Use your calculator in Engineering notation to Use your calculator in Engineering notation to find:find:

• 3.21 x 103.21 x 1055 x 12.98 x 10 x 12.98 x 1077 = =• 3.21 [EXP] 5 [x] 12.98 [EXP] 7 [=] 3.21 [EXP] 5 [x] 12.98 [EXP] 7 [=] 41.67 x 1041.67 x 101212 • Note: [EXP] may be [x10Note: [EXP] may be [x10XX] or [EE] or something ] or [EE] or something

else on your calculatorelse on your calculator• The answer was switched to Engineering The answer was switched to Engineering

Notation and rounded offNotation and rounded off

4444

ExampleExample

• Use ( ) around the terms in the Use ( ) around the terms in the denominator denominator

• 4.5 [x104.5 [x10xx] [ (-) ] 4 [÷] [(] 6 [x10] [ (-) ] 4 [÷] [(] 6 [x10xx] 5 [x]] 5 [x]7 [x107 [x10xx] [ (-) ] 8 [)] [ = ]] [ (-) ] 8 [)] [ = ]

• 1.07 x 101.07 x 10-2-2 OR 10.71 x 10 OR 10.71 x 10-3-3 in [ENG] in [ENG]

• Some TI calculators REQUIRE ( ) Some TI calculators REQUIRE ( ) when dividing in scientific notationwhen dividing in scientific notation

4545

4

5 8

4.5 10

6 10 7 10

x

x x x

Page 10, Problem 3, 4Page 10, Problem 3, 4NumberNumber EngineeringEngineering

(3.6x10(3.6x1044)(8.8x10)(8.8x10-4-4))

(-4.0x10(-4.0x10-6-6)(2.7x10)(2.7x10-1-1))

(-7.5x10(-7.5x1022)(-2.5x10)(-2.5x10-5-5))

(56x10(56x1033)(9.0x10)(9.0x10-7-7))

4646

9

3

(4.4 10 )

( 7.0 10 )

x

x2

6

(3.1 10 )

(41 10 )

x

x

Page 10, # 4Page 10, # 4NumberNumber Engineering

4747

4

6

( 2.0 10 )

( 6.5 10 )

x

x

3

2

(0.0033 10 )

( 15 10 )

x

x

PrefixesPrefixes• Engineers usually replace the power of ten Engineers usually replace the power of ten

with a prefixwith a prefix• Because all powers of 10 are multiples of Because all powers of 10 are multiples of

3 in Engineering Notation, we don’t have 3 in Engineering Notation, we don’t have so many to rememberso many to remember

• Some prefixes use Greek letters as Some prefixes use Greek letters as symbolssymbols

• Procedure to use a prefixProcedure to use a prefix– 1. 1. WriteWrite the quantity in engineering notation. the quantity in engineering notation.– 2. 2. ReplaceReplace the power of ten with its prefix. the power of ten with its prefix.

4848

Prefixes and SymbolsPrefixes and Symbols

Power of 10Power of 10 PrefixPrefix SymbolSymbol

1010-12-12 picopico pp

1010-9-9 nanonano nn

1010-6-6 micromicro µµ

1010-3-3 millimilli mm

Prefixes and SymbolsPrefixes and Symbols

Power of 10Power of 10 PrefixPrefix SymbolSymbol

101033 kilokilo kk

101066 megamega MM

101099 gigagiga GG

10101212 teratera TT

The prefix symbols Y (yotta), Z (zetta), E (exa), P (peta), T (tera), G (giga), and M (mega) are printed in upper-case letters while all other prefix symbols are printed in lower-case letters

UnitsUnits• In electronics, measurements always In electronics, measurements always

have a number and a unithave a number and a unit

• Units are a vital part of your answerUnits are a vital part of your answer

• Answers to problems include a Answers to problems include a number in Engineering Notation, with number in Engineering Notation, with the proper prefix substituted for the the proper prefix substituted for the power of 10, and the correct unitpower of 10, and the correct unit

5151

Seven Basic UnitsSeven Basic Units5252

SI Fundamental UnitsQuantityQuantity UnitUnit SymbolSymbol

LengthLength MeterMeter mm

MassMass KilogramKilogram kg kg

TimeTime SecondSecond ss

Electric currentElectric current ampereampere AA

TemperatureTemperature KelvinKelvin KK

Luminous Luminous IntensityIntensity

CandelaCandela cdcd

Amount of Amount of substancesubstance

MoleMole molmol

Electrical UnitsElectrical Units5353

SI Fundamental UnitsQuantityQuantity SymbolSymbol UnitUnit SymbolSymbol

ChargeCharge QQ coulombcoulomb CC

CurrentCurrent II ampereampere AA

Energy - WorkEnergy - Work WW joulejoule JJ

PowerPower PP wattwatt WW

ResistanceResistance RR ohmohm ΩΩ

VoltageVoltage VV voltvolt VV

ConductanceConductance GG siemenssiemens SS

CapacitanceCapacitance CC faradfarad FF

FrequencyFrequency ff HertzHertz HzHz

InductanceInductance II HenryHenry HH

CapitalizationCapitalization• Unit symbols are printed in Unit symbols are printed in

lower-case letters except lower-case letters except that the symbol or the first letter of the that the symbol or the first letter of the symbol is an upper-case letter when the symbol is an upper-case letter when the name of the unit is derived from the name of name of the unit is derived from the name of a person (Except liter = L, not l)a person (Except liter = L, not l)

• When spelled out in full, unit names are When spelled out in full, unit names are treated like ordinary English nouns. treated like ordinary English nouns.

• Thus the names of all units start with a Thus the names of all units start with a lower-case letterlower-case letter, except at the beginning of , except at the beginning of a sentence or in capitalized material such as a sentence or in capitalized material such as a title.a title.

5454

PracticePracticeQuantityQuantity Unit of MeasurementUnit of Measurement

resistanceresistance OhmOhm

currentcurrent

voltagevoltage

energyenergy

powerpower

conductanceconductance

chargecharge

5555

More PracticeMore PracticeUnitUnit Symbol for Symbol for

UnitUnitQuantity Quantity measuredmeasured

ohmohm ΩΩ

voltvolt

wattwatt

ampereampere

coulombcoulomb

joulejoule

siemenssiemens

5656

ExampleExample• If your calculator displays If your calculator displays

5.678 x 105.678 x 1066, the equivalent , the equivalent metric value is:metric value is:

• Replace the power of 10 with the Replace the power of 10 with the symbolsymbol

• Because 10Because 1066 = M = M

• 5.678 x 105.678 x 106 = 6 = 5.678 M or (round off)5.678 M or (round off)

• 5.68 M5.68 M

• (Most times a unit is REQUIRED!)(Most times a unit is REQUIRED!)

5757101066=M =M 101033=k=k1010-3-3 = m = m1010-6 -6 = = μμ1010-9-9 = n = n

Table 1-5, Column 3, Page 8Table 1-5, Column 3, Page 8NumberNumber Metric ValueMetric Value

0.0829 V0.0829 V 82.9 mV82.9 mV

48,000 Hz48,000 Hz

2,200,000 2,200,000 ΩΩ

0.000 015 A0.000 015 A

7,500 W7,500 W

0.000 000 033 F0.000 000 033 F

270,000 270,000 ΩΩ

0.000 010 H0.000 010 H

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Table 1-6, Page 8Table 1-6, Page 8Metric ValueMetric Value Engineering NotationEngineering Notation

100 pF100 pF 100 x 10100 x 10-12-12 F F

12 kV12 kV

85.0 85.0 μμAA

50 GHz50 GHz

33 k33 kΩΩ

250 mV250 mV

7.8 ns7.8 ns

2.0 M2.0 MΩΩ

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Page 22, Problem 17Page 22, Problem 17QuantityQuantity Engineering PrefixEngineering Prefix

1.24 x101.24 x10-6-6 A A 1.24 1.24 μμAA

7.5 x 107.5 x 1033 ΩΩ

4.7 x 104.7 x 1044 Hz Hz

3.3 x 103.3 x 10-8-8 F F

2.2 x 102.2 x 10-12 -12 ss

9.5 x 109.5 x 10-2-2 H H

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Page 10, Problem 1Page 10, Problem 16161

Metric prefix and Metric prefix and unitunit

Exponent Exponent expression and expression and unit symbolunit symbol

Prefix and Prefix and unitunit

kilowattkilowatt 101033 W W kWkW

milliamperemilliampere

picofaradpicofarad

nanosecondnanosecond

megohmmegohm

microhenrymicrohenry

Page 10, Problem 2Page 10, Problem 26262

AbbreviationAbbreviation Full written expressionFull written expression

MWMW MegawattMegawatt

nAnA

μμJJ

mVmV

kkΩΩ

GHzGHz

Unit ConversionsUnit Conversions• To convert units, multiply by a useful To convert units, multiply by a useful

value of 1value of 1

• Because 1 foot = 12 inches, then:Because 1 foot = 12 inches, then:

• The top and bottom at the sameThe top and bottom at the same

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139 3.25

12

footinches feet

inches

1 121

12 1

foot inches

inches foot

Unit ConversionsUnit Conversions• Convert 0.00058 microvolts (μV) to the Convert 0.00058 microvolts (μV) to the

equivalent picovolts (pV).equivalent picovolts (pV).

• Do NOT put in values for Do NOT put in values for μμ as these as these values cancelvalues cancel

• Keep the “p” as isKeep the “p” as is• This is the “chain” rule used in This is the “chain” rule used in

advanced coursesadvanced courses

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12

6

10.00058 580

10

pV pV

Another MethodAnother Method• The books suggests moving the The books suggests moving the

decimal pointdecimal point

• Let your calculator do the workLet your calculator do the work

• Enter 0.00058 x 10Enter 0.00058 x 10-6-6 and hit the equal and hit the equal sign and [ENG] to get: 580 x 10sign and [ENG] to get: 580 x 10-12-12

• Since 10Since 10-12-12 = p, we get = p, we get

• 0.00058 microvolts = 580 pV0.00058 microvolts = 580 pV

• Entering [ENG] again or [SHIFT] Entering [ENG] again or [SHIFT] [Eng] moves to another unit[Eng] moves to another unit

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ExampleExample• Convert .005 A to Convert .005 A to μμAA

• Enter .00Enter .0055 and press [=] to get: and press [=] to get:

• 5 x 105 x 10-3-3

• Press [ENG] again to get:Press [ENG] again to get:

• 5000 x 105000 x 10-6 -6 = 5000 = 5000 μμAA

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ConversionsConversions6767

ValueValue ConversionConversion

3,200 3,200 μμWW WW

5,000 kV5,000 kV VV

10 MW10 MW kWkW

1 ma1 ma μμaa

0.05 kV0.05 kV mVmV

0.02 k0.02 kΩΩ MMΩΩ

155 mW155 mW kWkW

Measured NumbersMeasured Numbers• Any time you make a measurement, Any time you make a measurement,

the recorded data is never perfectthe recorded data is never perfect– Every measurement has some amount Every measurement has some amount

of error in it – alwaysof error in it – always

• AccurateAccurate measurements are measurements are measurements that are close to the measurements that are close to the true or accepted valuetrue or accepted value

• PrecisePrecise measurements are measurements are consistently close to each otherconsistently close to each other

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MeasurementsMeasurements• Experimental uncertainty is Experimental uncertainty is

part of all measurements. part of all measurements. • Error is the difference between the true Error is the difference between the true

or best accepted value and the or best accepted value and the measured value. measured value.

• Accuracy is an Accuracy is an indication of the rangeindication of the range of error in a of error in a measurementmeasurement

• Precision is a measure of repeatabilityPrecision is a measure of repeatability

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.

Error, Accuracy, and Precision

Error}

Precise, but not accurate.

Precision and AccuracyPrecision and Accuracy• Precise and accuratePrecise and accurate Accurate onlyAccurate only

• Precise onlyPrecise only Neither Accurate nor precise Neither Accurate nor precise

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Meter MeasurementsMeter Measurements• Digital meters do not depend on the Digital meters do not depend on the

user’s judgment user’s judgment

• We all see We all see 1.55 VDC 1.55 VDC and 47.5 and 47.5 ΩΩ

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DMMDMM• You will use Digital Multi-Meters You will use Digital Multi-Meters

(DMM) in class(DMM) in class

• On the job, you might have to deal On the job, you might have to deal with analog meterswith analog meters

• Digital meters still estimate the last Digital meters still estimate the last digitdigit

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Significant FiguresSignificant Figures• Every non-zero number you Every non-zero number you

measure, including the one measure, including the one estimated digit, is significantestimated digit, is significant

• If you measure a “0” to the right of a number, If you measure a “0” to the right of a number, it is significantit is significant

• 0s that are place holders are 0s that are place holders are notnot significant significant (to the left of all other digits)(to the left of all other digits)

• You measure the width of a credit card as 5.40 You measure the width of a credit card as 5.40 cm. Your best estimate is NOT 5.41 cm or 5.39 cm. Your best estimate is NOT 5.41 cm or 5.39 cm. The 0 is measured and significantcm. The 0 is measured and significant

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Significant FiguresSignificant Figures• When measurements are written in When measurements are written in

scientific notation, every digit in the scientific notation, every digit in the number is number is significantsignificant

• All the digits except the right most digit All the digits except the right most digit are certain.are certain.

• Which digits are significant in:Which digits are significant in:• 3.450 x 103.450 x 1088____________________________

• 4.87 x 104.87 x 10 -4 -4 ____________________________

• Scientists do NOT waste time writing Scientists do NOT waste time writing down non-significant digitsdown non-significant digits

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Place HoldersPlace Holders

• 5.40 cm has 3 significant figure5.40 cm has 3 significant figure• Expressed as meters, the number is Expressed as meters, the number is

0.0540 m. (and 0.0000540 km)0.0540 m. (and 0.0000540 km)• There are still only three digits that There are still only three digits that

you measured, so there are 3 you measured, so there are 3 significant figures.significant figures.

• Scientist conserve energy. They don’t Scientist conserve energy. They don’t write 0s at the end of a number unless write 0s at the end of a number unless they are measured and so significantthey are measured and so significant

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ExamplesExamples

• State the number of significant State the number of significant digits:digits:

• 1.00 x 101.00 x 1033 _________ _________

• 0.0057 ____________0.0057 ____________

• 1502.0 ______________1502.0 ______________

• 0.000036 _____________0.000036 _____________

• 0.105 ___________0.105 ___________

• 2.6 x 102.6 x 1022 __________ __________

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CalculationsCalculations

• From now on, most of your From now on, most of your calculations will be done using calculations will be done using scientific notation and significant scientific notation and significant figuresfigures

• Believe it or not, it can make your life Believe it or not, it can make your life easier! Trust Me!!easier! Trust Me!!

• Many rules apply, but for now, Many rules apply, but for now, THREE significant figures is a good THREE significant figures is a good compromise.compromise.

Rounding OffRounding Off• You keep all digits in all calculations You keep all digits in all calculations

until your final answeruntil your final answer

• You round off your final answer to You round off your final answer to the correct number of significant the correct number of significant figuresfigures

• In this class, usually THREE In this class, usually THREE significant figures is sufficientsignificant figures is sufficient

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Rounding Rules Rounding Rules • If the digits dropped are greater than If the digits dropped are greater than

5, like 698 or 501 increase the last 5, like 698 or 501 increase the last retained digit by 1.retained digit by 1.

• 13.13.11698 = 13.698 = 13.22 23. 23.44501 = 23.501 = 23.55

• If the digit dropped is less than 5, do If the digit dropped is less than 5, do not change the last retained digit.not change the last retained digit.

• 3344.456 = 34 33..456 = 34 33.5533 = 33.33 = 33.55

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Round to Even RuleRound to Even Rule• If the digits dropped are 50000…., If the digits dropped are 50000….,

increase the last retained digit if it increase the last retained digit if it makes it even, otherwise do not. makes it even, otherwise do not.

• 12.345 = 12.3412.345 = 12.34

• 12.355 = 12.3612.355 = 12.36

• Note:Note:

• 12.3451 = 12.3512.3451 = 12.35

• Example 1-22 (e) is wrong in the text.Example 1-22 (e) is wrong in the text.

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ExamplesExamples• Switch to Engineering notation and Switch to Engineering notation and

round to 3 significant figuresround to 3 significant figures

• Use the “round-to-even” ruleUse the “round-to-even” rule

• 50,505 ______________50,505 ______________

• 220.45 ______________220.45 ______________

• 4646 ______________4646 ______________

• 10.99 ______________10.99 ______________

• 1.005 ______________1.005 ______________

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Safety SuggestionsSafety Suggestions• Do not work alone, or when you are drowsy.Do not work alone, or when you are drowsy.• Wear rubber-soled shoes and stand on Wear rubber-soled shoes and stand on

insulated mats if floor is conductiveinsulated mats if floor is conductive• Wear safety glasses when clipping wires or Wear safety glasses when clipping wires or

soldering.soldering.• Know the potential hazards of the equipment you Know the potential hazards of the equipment you

are working on; check equipment and power cords are working on; check equipment and power cords frequently.frequently.

• Avoid all contact with energized circuits; even low Avoid all contact with energized circuits; even low voltage circuits.voltage circuits.

• Know the location of power Know the location of power shutoff and fire extinguishers.shutoff and fire extinguishers.

• Don’t have food or drinks Don’t have food or drinks in the laboratory or work area. in the laboratory or work area.

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Home SafetyHome Safety

• Regular and GFCI (Ground Fault Regular and GFCI (Ground Fault Circuit Interrupter)Circuit Interrupter)

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Built-in ProtectionBuilt-in Protection• In a “good” circuit, the current In a “good” circuit, the current

coming out of the socket from the coming out of the socket from the black or “hot” wire is matched by the black or “hot” wire is matched by the current returning to the white or current returning to the white or “neutral” wire“neutral” wire

• The GFCI stops all current flow if The GFCI stops all current flow if there is not a perfect match, there is not a perfect match, assuming some of the missing assuming some of the missing current is going through YOUcurrent is going through YOU

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Chapter SummaryChapter Summary• Scientific notation is a method for Scientific notation is a method for

expressing very large and very small expressing very large and very small numbers as a number between one numbers as a number between one and ten (one digit to left of decimal and ten (one digit to left of decimal point) times a power of ten. point) times a power of ten.

• Engineering notation is a form of Engineering notation is a form of scientific notation in which scientific notation in which quantities are expressed with one, quantities are expressed with one, two, or three digits to the left of the two, or three digits to the left of the decimal point times a power of ten decimal point times a power of ten that is a multiple of three. that is a multiple of three.

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Chapter SummaryChapter Summary• Metric prefixes are symbols used to Metric prefixes are symbols used to

represent powers of ten that are represent powers of ten that are multiples of three. multiples of three.

• The uncertainty of a measured The uncertainty of a measured quantity depends on the accuracy quantity depends on the accuracy and precision of the measurement. and precision of the measurement.

• The number of significant digits in The number of significant digits in the result of a mathematical the result of a mathematical operation should never exceed the operation should never exceed the significant digits in the original significant digits in the original numbers. numbers.

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