Basic Electronics Ninth Edition Grob Schultz ©2002 The McGraw-Hill Companies Basic Electronics Ninth Edition CHAPTER Alternating Voltage and Current ©2003 The McGraw-Hill Companies.
Download ReportTranscript Basic Electronics Ninth Edition Grob Schultz ©2002 The McGraw-Hill Companies Basic Electronics Ninth Edition CHAPTER Alternating Voltage and Current ©2003 The McGraw-Hill Companies.
Slide 1
Basic Electronics
Ninth Edition
Grob
Schultz
©2002 The McGraw-Hill Companies
Slide 2
Basic Electronics
Ninth Edition
CHAPTER
16
Alternating Voltage
and Current
©2003 The McGraw-Hill Companies
Slide 3
Topics Covered in Chapter 16
Alternating Current Applications
Alternating-Voltage Generator
The Sine Wave
Alternating Current
Voltage and Current Values for a
Sine Wave
Slide 4
Topics Covered in Chapter 16
(continued)
Frequency
Period and Wavelength
Phase Angle
The Time Factor in Frequency
and Phase
AC Circuits with Resistance
Slide 5
Topics Covered in Chapter 16
(continued)
Nonsinusoidal AC Waveforms
Harmonic Frequencies
The 60-Hz AC Power Line
Motors and Generators
Three-Phase AC Power
Slide 6
A loop rotating in a magnetic field
generates a sine wave.
1 cycle
(360°)
+V
N
Vmax
0
S
-V
Vinstantaneous = Vmax• sin
Slide 7
Elements of a Sine Wave
• Alternating voltage and current vary
continuously in magnitude and reverse in
polarity.
• One complete set of values is one cycle of
the ac waveform.
• One cycle includes 360° in angular
measure or 2p rad in radian measure.
Slide 8
Amplitude
Angular Measure
0
0°
0 rad
90 °
180 °
270 °
360 °
p/2 rad p rad 3p/2 rad 2p rad
Slide 9
Sine Wave Amplitudes
• The rms value is 0.707 peak value.
• The peak amplitude is 1.414 rms
value.
• The peak-to-peak value is 2.828
rms value.
• The average value is 0.637 peak
value.
Slide 10
Sine Wave Amplitudes
Amplitude
(Two cycles shown)
Vav
Vrms
Vp-p
Vp
0
360°
Vp-p = 2 x Vp
Vrms = 0.707 x Vp
720°
Vav = 0.637 x Vp
Slide 11
The default amplitude measurement is Vrms .
120 V
100 W
Vrms is the effective value.
The heating effect of these
two sources is identical.
+
120 V
100 W
Same power
dissipation
Slide 12
The average value is zero for the
entire cycle.
Amplitude
+ 10 V
Vav = + 6.37 V
The pos. alternation
0
- 10 V
Vav = - 6.37 V
The neg. alternation
Vav = 0 V
Slide 13
Frequency of a Waveform
Frequency (f) is the number of cycles per
second.
One cycle per second is 1 Hz
Audio range is 16 to 16,000 Hz
Radio-frequency range is up to 300,000
MHz (300 GHz)
Slide 14
Sine Wave Frequency
Amplitude
(Two cycles shown)
0
Time
0.5 sec
f = 2 Hz
1 sec
Slide 15
Period of a Waveform
Period (T) is the time per cycle.
T = 1/f
f = 1/T
The higher the frequency, the
shorter the period.
Slide 16
Period (T)
Amplitude
T
0
Time
0.0167 s
f = 1/T = 1/.0167 = 60 Hz
Slide 17
Wavelength of a Waveform
Wavelength (l) is the distance a wave
travels in one cycle.
l = v/f, where:
l = wavelength
v = velocity of wave (such as sound or light)
f = frequency
The higher the frequency the lower the
wavelength.
The velocity of a radio wave is 3 x 108 meters/s.
Slide 18
Wavelength
l
27 MHz
Radio
Transmitter
l = v/f = 3 x 108/27 MHz = 11.1 meters
Slide 19
Phase of a Waveform
Phase angle () is the angular difference
between the same points on two different
waveforms of the same frequency.
Two waveforms that have peaks and zeros at the
same time are in phase and have a phase angle of 0°.
When one sine wave is at its peak while another is at
zero, the two are 90° out of phase.
When one sine wave has just the opposite phase of
another, they are 180° out of phase.
Slide 20
Amplitude
Phase
0
= 0
The waveforms are in phase.
Slide 21
Amplitude
Phase
0
= 180
The waveforms are not in phase.
Slide 22
Amplitude
Phase
0
= 90
The waveforms are not in phase.
Slide 23
Phasor Representation
• Similar to vectors, phasors indicate the
amplitude and phase angle of ac voltage
or current.
• The length of the phasor represents the
amplitude of the waveform.
• The angle represents the phase angle of
the waveform.
Slide 24
Phasor Representation
Amplitude
= 90
0
Slide 25
Amplitude
Phasor Representation
0
= 180
Slide 26
Common AC Waveforms
• Sine wave
• Square wave *
• Sawtooth wave *
• Pulse wave *
* nonsinusoidal waveforms.
Slide 27
Additional Notes
• House wiring uses 3-wire, single-phase power.
• The frequency of house wiring is 60 Hz.*
• The voltages for house wiring are 120 V to
ground, and 240 V across the two high sides.
• Three-phase ac power has three legs that are
120° out of phase.
*Many places outside N. America use a 50
Hz standard for house wiring.
Slide 28
Three Loops Rotating in a Magnetic Field
NN
SS
Vinstantaneous
(3 values)
Basic Electronics
Ninth Edition
Grob
Schultz
©2002 The McGraw-Hill Companies
Slide 2
Basic Electronics
Ninth Edition
CHAPTER
16
Alternating Voltage
and Current
©2003 The McGraw-Hill Companies
Slide 3
Topics Covered in Chapter 16
Alternating Current Applications
Alternating-Voltage Generator
The Sine Wave
Alternating Current
Voltage and Current Values for a
Sine Wave
Slide 4
Topics Covered in Chapter 16
(continued)
Frequency
Period and Wavelength
Phase Angle
The Time Factor in Frequency
and Phase
AC Circuits with Resistance
Slide 5
Topics Covered in Chapter 16
(continued)
Nonsinusoidal AC Waveforms
Harmonic Frequencies
The 60-Hz AC Power Line
Motors and Generators
Three-Phase AC Power
Slide 6
A loop rotating in a magnetic field
generates a sine wave.
1 cycle
(360°)
+V
N
Vmax
0
S
-V
Vinstantaneous = Vmax• sin
Slide 7
Elements of a Sine Wave
• Alternating voltage and current vary
continuously in magnitude and reverse in
polarity.
• One complete set of values is one cycle of
the ac waveform.
• One cycle includes 360° in angular
measure or 2p rad in radian measure.
Slide 8
Amplitude
Angular Measure
0
0°
0 rad
90 °
180 °
270 °
360 °
p/2 rad p rad 3p/2 rad 2p rad
Slide 9
Sine Wave Amplitudes
• The rms value is 0.707 peak value.
• The peak amplitude is 1.414 rms
value.
• The peak-to-peak value is 2.828
rms value.
• The average value is 0.637 peak
value.
Slide 10
Sine Wave Amplitudes
Amplitude
(Two cycles shown)
Vav
Vrms
Vp-p
Vp
0
360°
Vp-p = 2 x Vp
Vrms = 0.707 x Vp
720°
Vav = 0.637 x Vp
Slide 11
The default amplitude measurement is Vrms .
120 V
100 W
Vrms is the effective value.
The heating effect of these
two sources is identical.
+
120 V
100 W
Same power
dissipation
Slide 12
The average value is zero for the
entire cycle.
Amplitude
+ 10 V
Vav = + 6.37 V
The pos. alternation
0
- 10 V
Vav = - 6.37 V
The neg. alternation
Vav = 0 V
Slide 13
Frequency of a Waveform
Frequency (f) is the number of cycles per
second.
One cycle per second is 1 Hz
Audio range is 16 to 16,000 Hz
Radio-frequency range is up to 300,000
MHz (300 GHz)
Slide 14
Sine Wave Frequency
Amplitude
(Two cycles shown)
0
Time
0.5 sec
f = 2 Hz
1 sec
Slide 15
Period of a Waveform
Period (T) is the time per cycle.
T = 1/f
f = 1/T
The higher the frequency, the
shorter the period.
Slide 16
Period (T)
Amplitude
T
0
Time
0.0167 s
f = 1/T = 1/.0167 = 60 Hz
Slide 17
Wavelength of a Waveform
Wavelength (l) is the distance a wave
travels in one cycle.
l = v/f, where:
l = wavelength
v = velocity of wave (such as sound or light)
f = frequency
The higher the frequency the lower the
wavelength.
The velocity of a radio wave is 3 x 108 meters/s.
Slide 18
Wavelength
l
27 MHz
Radio
Transmitter
l = v/f = 3 x 108/27 MHz = 11.1 meters
Slide 19
Phase of a Waveform
Phase angle () is the angular difference
between the same points on two different
waveforms of the same frequency.
Two waveforms that have peaks and zeros at the
same time are in phase and have a phase angle of 0°.
When one sine wave is at its peak while another is at
zero, the two are 90° out of phase.
When one sine wave has just the opposite phase of
another, they are 180° out of phase.
Slide 20
Amplitude
Phase
0
= 0
The waveforms are in phase.
Slide 21
Amplitude
Phase
0
= 180
The waveforms are not in phase.
Slide 22
Amplitude
Phase
0
= 90
The waveforms are not in phase.
Slide 23
Phasor Representation
• Similar to vectors, phasors indicate the
amplitude and phase angle of ac voltage
or current.
• The length of the phasor represents the
amplitude of the waveform.
• The angle represents the phase angle of
the waveform.
Slide 24
Phasor Representation
Amplitude
= 90
0
Slide 25
Amplitude
Phasor Representation
0
= 180
Slide 26
Common AC Waveforms
• Sine wave
• Square wave *
• Sawtooth wave *
• Pulse wave *
* nonsinusoidal waveforms.
Slide 27
Additional Notes
• House wiring uses 3-wire, single-phase power.
• The frequency of house wiring is 60 Hz.*
• The voltages for house wiring are 120 V to
ground, and 240 V across the two high sides.
• Three-phase ac power has three legs that are
120° out of phase.
*Many places outside N. America use a 50
Hz standard for house wiring.
Slide 28
Three Loops Rotating in a Magnetic Field
NN
SS
Vinstantaneous
(3 values)