chap01 of floyd

Electronics Fundamentals 8th edition Floyd/Buchla

© 2010 Pearson Education, Upper Saddle River, NJ 07458. All Rights Reserved.

chapter 1

electronics fundamentalscircuits, devices, and applications

THOMAS L. FLOYDDAVID M. BUCHLA


Chapter 1Chapter 1


Very large and very small numbers are represented with scientific and engineering notation.

Scientific and Engineering Notation

47,000,000 = 4.7 x 107 (Scientific Notation)

= 47 x 106 (Engineering Notation)


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0.000 027 = 2.7 x 10-5 (Scientific Notation)

= 27 x 10-6 (Engineering Notation)

0.605 = 6.05 x 10-1 (Scientific Notation)

= 605 x 10-3 (Engineering Notation)

Scientific and Engineering Notation


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

Metric Conversions

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


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SI Fundamental Units

Length Mass

Time

Electric current

Temperature

Luminous intensity

Amount of substance

Quantity Unit Symbol

Meter m

Kilogram kg

Second s

Ampere A

Kelvin K

Candela cd

Mole mol


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Some Important Electrical Units

Except for current, all electrical and magnetic units are derived from the fundamental units. Current is a fundamental unit.

CurrentCharge

Voltage

Resistance

Ampere A

Coulomb C

Volt V

Ohm Watt W

Quantity Unit Symbol

Power

These derived units are based on fundamental units from the meter-kilogram-second system, hence are called mks units.


Chapter 1Chapter 1


Engineering Metric Prefixes

peta

tera

giga

mega

kilo

1015

1012

109

106

103

P

T

G

M

k

Can you name the prefixes and their meaning?


Chapter 1Chapter 1


Engineering Metric Prefixes

10-3

10-6

10-9

10-12

10-15

milli

micro

nano

pico

femto

m

n

p

f

Can you name the prefixes and their meaning?


Chapter 1Chapter 1


When converting from a larger unit to a smaller unit, move the decimal point to the right. Remember, a smaller unit means the number must be larger.

Metric Conversions

0.47 M = 470 k

Larger number

Smaller unit


Chapter 1Chapter 1


When converting from a smaller unit to a larger unit, move the decimal point to the left. Remember, a larger unit means the number must be smaller.

Metric Conversions

10,000 pF = 0.01 F

Smaller number

Larger unit


Chapter 1Chapter 1


When adding or subtracting numbers with a metric prefix, convert them to the same prefix first.

Metric Arithmetic

10,000 + 22 k =

10,000 + 22,000 = 32,000

Alternatively,

10 k + 22 k = 32 k


Chapter 1Chapter 1


When adding or subtracting numbers with a metric prefix, convert them to the same prefix first.

Metric Arithmetic

200 + 1.0 mA =

200 A + 1,000 A = 1,200 A

Alternatively,

0.200 m + 1.0 mA = 1.2 mA


Chapter 1Chapter 1


Experimental uncertainty is part of all measurements. Error is the difference between the true or best accepted value and the measured value. Accuracy is an indication of the range of error in a measurement.

Error, Accuracy, and Precision

Error}

Precision is a measure of repeatability.

Precise, but not accurate.


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Significant Digits

When reporting a measured value, one uncertain digit may be retained but other uncertain digits should be discarded. Normally this is the same number of digits as in the original measurement.

Assume two measured quantities are 10.54 and 3.92. If the larger is divided by the smaller, the answer is 2.69 becausethe answer has the same uncertainty as the original measurement.


Chapter 1Chapter 1


Rules for determining if a reported digit is significant are:

1. Nonzero digits are always considered to be significant.

2. Zeros to the left of the first nonzero digit are never significant.

3. Zeros between nonzero digits are always significant.

4. Zeros to the right of the decimal point for a decimal number are significant.

5. Zeros to the left of the decimal point with a whole number may or may not be significant depending on the measurement.

Significant Digits


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1. Nonzero digits are always considered to be significant.

2. Zeros to the left of the first nonzero digit are never significant.

3. Zeros between nonzero digits are always significant.

4. Zeros to the right of the decimal point for a decimal number are significant.

5. Zeros to the left of the decimal point with a whole number may or may not be significant depending on the measurement.

Example: 23.92 has four nonzero digits – they are all significant.

Example: 0.00276 has three zeros to the left of the first nonzero digit. There are only three significant digits.

Example: 806 has three significant digits.

Example: 9.00 has three significant digits.

Example: 4000 does not have a clear number of significant digits.


Chapter 1Chapter 1


Rounding numbers

1. If the digit dropped is greater than 5, increase the last retained digit by 1.

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

3. If the digit dropped is 5, increase the last retained digit if it makes it even, otherwise do not. This is called the "round-to-even" rule.

Rounding is the process of discarding meaningless digits. Rules for rounding are:


Chapter 1Chapter 1


Utility voltages and GFIC

Most laboratory equipment is connected to 120 Vrms at the outlet. Wiring to the outlets generally uses three insulated wires which are referred to as the “hot” (black or red wire), neutral (white wire), and safety ground (green wire).

NeutralHot

Ground

GFIC circuits can detect a difference in the hot and neutral current and trip a breaker. One outlet on the circuit will have reset and test buttons.

Notice that neutral is

larger than the hot line.


Chapter 1Chapter 1


Electrical Safety

• Do not work alone, or when you are drowsy.• Do not wear conductive jewelry.• Know the potential hazards of the equipment you are

working on; check equipment and power cords frequently.• Avoid all contact with energized circuits; even low voltage

circuits.• Maintain a clean workspace.• Know the location of power shutoff and fire extinguishers.• Don’t have food or drinks in the laboratory or work area.

Safety is always a concern with electrical circuits. Knowing the rules and maintaining a safe environment is everyone’s job. A few important safety suggestions are:


Chapter 1Chapter 1


Engineering notation

Exponent

Metric prefix

Power of ten

A system for representing any number as a one-, two-, or three-digit number times a power of ten with an exponent that is a multiple of three.

The number to which a base is raised.

A symbol that is used to replace the power of ten in numbers expressed in scientific or engineering notation.

Key Terms

A numerical representation consisting of a base of 10 and an exponent; the number 10 raised to a power.


Chapter 1Chapter 1


Scientific notation

Accuracy

Precision

Significant digit

An indication of the range of error in a measurement.

A measure of the repeatability (consistency) of a series of measurements.

A digit known to be correct in a number.

A system for representing any number as a number between 1 and 10 times a power of ten.

Key Terms


Chapter 1Chapter 1


Quiz

1. A number written as 2.59 x 107 is said to be in

a. scientific notation

b. engineering notation

c. both of the above

d. none of the above


Chapter 1Chapter 1


Quiz

2. The electrical unit that is fundamental is the

a. volt

b. ohm

c. coulomb

d. ampere


Chapter 1Chapter 1


Quiz

3. In scientific notation, the number 0.000 56 is written

a. 5.6 x 104

b. 5.6 x 10-4

c. 56 x 10-5

d. 560 x 10-6


Chapter 1Chapter 1


Quiz

4. In engineering notation, the number 0.000 56 is written

a. 5.6 x 104

b. 5.6 x 10-4

c. 56 x 10-5

d. 560 x 10-6


Chapter 1Chapter 1


Quiz

5. The metric prefix nano means

a. 10-3

b. 10-6

c. 10-9

d. 10-12


Chapter 1Chapter 1


Quiz

6. The metric prefix pico means

a. 10-3

b. 10-6

c. 10-9

d. 10-12


Chapter 1Chapter 1


Quiz

7. The number 2700 MW can be written

a. 2.7 TW

b. 2.7 GW

c. 2.7 kW

d. 2.7 mW


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Quiz

8. The value 68 k is equal to

a. 6.8 x 104

b. 68, 000

c. 0.068 M

d. All of the above


Chapter 1Chapter 1


Quiz

9. The sum of 330 mW + 1.5 W is

a. 331.5 mW

b. 3.35 W

c. 1.533 W

d. 1.83 W


Chapter 1Chapter 1


Quiz

10. Precision is a measurement of

a. the total error in a series of measurements

b. the consistency of a series of measurements

c. both of the above

d. none of the above


Chapter 1Chapter 1


Answers:

1. a

2. d

3. b

4. d

5. c

6. d

7. b

8. d

9. d

10. b

Quiz

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