Chapter 1
Components,
Quantities, and Units
ISU EE
C.Y. Lee
Objectives
Recognize common electrical components and
measuring instruments
State basic electrical and magnetic quantities and
their units
Use scientific notation to express quantities
Use engineering notation and metric prefixes to
express large and small quantities
Convert from one metric-prefixed unit to another
ISU EE
2
C.Y. Lee
Resistors
Resistors limit electrical current in a circuit
(Two common types of individual fixed resistors)
ISU EE
3
C.Y. Lee
Resistors
(Chip resistor and resistor networks)
(Common types of variable resistors)
ISU EE
4
C.Y. Lee
Capacitors
Capacitors store electrical charge and are used to
block dc and pass ac
radial
(Common types of
fixed capacitors)
radial
radial
ISU EE
5
C.Y. Lee
Capacitors
(Typical variable capacitors)
ISU EE
6
C.Y. Lee
Inductors
Inductors, or coils, are used to store energy in an
electromagnetic field
(Some fixed and variable inductors)
ISU EE
7
C.Y. Lee
Transformers
Transformers are used for ac coupling, or to
increase/decrease ac voltages
ISU EE
8
C.Y. Lee
Semiconductor Devices
Wide selection of packages are used for semiconductor devices,
depending on the function and the power requirements
ISU EE
9
C.Y. Lee
Power Supply
A dc power supply provides current and voltage to
power electronic circuits
ISU EE
10
C.Y. Lee
Function Generator
A function generator provides electronic signals
for our circuits
ISU EE
11
C.Y. Lee
Digital Multimeter
A digital multimeter (DMM) measures voltage,
current or resistance, depending upon the
function selected
– A voltmeter is used to measure
voltage across a component or
circuit
– An ammeter is used to measure
current through a circuit
– An ohmmeter is used to measure
resistance
ISU EE
12
C.Y. Lee
Oscilloscope
The oscilloscope us used
for observing and
measuring ac voltage
signals in a circuit
Digital storage scopes are
able to store waveforms
Some digital scopes are
can perform analysis on
waveforms
ISU EE
13
C.Y. Lee
Electrical Units
Letters are used in electronics to represent
quantities and units
The units and symbols are defined by the SI
system
– The term SI is the French abbreviation for
System International
Example:
I = 20 A, V = 110 V, R = 50 Ω, C = 0.1 F.
ISU EE
14
C.Y. Lee
Electrical Units
ISU EE
15
C.Y. Lee
Magnetic Units
Letters are also used to represent magnetic
quantities and units in the SI system
ISU EE
16
C.Y. Lee
Scientific Notation
Scientific notation is a convenient method of
expressing large and small numbers
A quantity is expressed as a number between 1 and
10, and a power of ten
Example:
5000 = 5 × 103
0.3 = 3 × 10-1
ISU EE
85,000 = 8.5 × 104
0.00063 = 6.3 × 10-4
17
C.Y. Lee
Engineering Notation
Engineering notation is similar to Scientific
notation, except that engineering notation can have
from 1 to 3 digits to the left of the decimal place,
and the powers of 10 are multiples of 3
Example:
82,000 = 82 × 103
0.0022 = 2.2 × 10-3
ISU EE
1,956,000 = 1.956 × 106
0.00033 = 330 × 10-6
18
C.Y. Lee
Metric Prefixes
Metric prefixes are symbols that represent the
powers of ten used in Engineering notation
ISU EE
19
C.Y. Lee
Example of Metric Prefix
(a) 50,000 V = 50 × 103 V = 50 kV
(b) 25,000,000 Ω = 25 × 106 Ω = 25 MV
(c) 0.0000367 A = 36.7 × 10-6 A = 36.7 µA
(d) 0.000000000005 F = 5 × 10-12 F = 5 pF
ISU EE
20
C.Y. Lee
Scientific Notation vs
Engineering Notation
Consider the number: 23,000
In Scientific notation it would be expressed as:
2.3 × 104
In Engineering notation it would be expressed as:
23 × 103
ISU EE
21
C.Y. Lee
Metric Unit Conversions
When converting from a larger unit to a smaller
unit, move the decimal point to the right
0.52 mA = 0.52 × 10-3 A = 520 × 10-6 A = 520 µA
When converting from a smaller unit to a larger
unit, move the decimal point to the left
700 nF = 700 × 10-9 F = 0.7 × 10-6 F = 0.7 µF
ISU EE
22
C.Y. Lee
Summary
Resistors limit electric current
Capacitors store electrical charge
Inductors store energy in their electromagnetic field
Transformers magnetically couple ac voltages, and
may step these voltages up/down
Power supplies provide current and voltage
Digital multimeters (DMM) measure voltage, current
and resistance
Function generators provide electronic signals for
our circuits
ISU EE
23
C.Y. Lee
Summary
An oscilloscope is used for observing and
measuring voltages in a circuit
Scientific notation expresses a number as one digit
to the left of the decimal point times a power of ten
Engineering notation expresses a number as one,
two or three digits to the left of the decimal point
times a power of ten that is a multiple of 3
Metric prefixes are symbols that represent the
powers of ten
ISU EE
24
C.Y. Lee