This document discusses power amplifiers and provides information on several key topics:
- Power amplifiers are classified based on the percentage of time the collector current is non-zero, with classes including A, B, and C.
- Class A amplifiers have the lowest theoretical maximum efficiency of 25% since the collector current is always on.
- The document provides equations to calculate input power, output power, and efficiency for different amplifier classes and configurations.
- A transformer-coupled class A amplifier is described that uses a transformer to couple the output signal from the amplifier to the load.
An Amplifier receives a signal from some pickup transducer or other input source and
provides a larger version of the signal to some output device or to another amplifier stage.
An input transducer signal is generally small (a few millivolts from a cassette or CD input or a
few microvolts from an antenna) and needs to be amplified sufficiently to operate an output
device (speaker or other power handling device). In small signal amplifiers, the main factors
are usually amplification linearity and magnitude of gain, since signal voltage and current are
small in a small-signal amplifier, the amount of power-handling capacity and power efficiency
are of little concern. A voltage amplifier provides voltage amplification primarily to increase
the voltage of the input signal. Large-signal or power amplifiers, on the other hand, primarily
provide sufficient power to an output load to drive a speaker or other power device, typically
a few watts to tens of watts. In the present chapter, we concentrate on those amplifier circuits
used to handle large-voltage signals at moderate to high current levels. The main features of
a large-signal amplifier are the circuit's power efficiency, the maximum amount of power that
the circuit is capable of handling, and the impedance matching to the output device. One
method used to categorize amplifiers is by class. Basically, amplifier classes represent the
amount the output signal varies over one cycle of operation for a full cycle of input signal. A
brief description of amplifier classes is provided next.
An Amplifier receives a signal from some pickup transducer or other input source and
provides a larger version of the signal to some output device or to another amplifier stage.
An input transducer signal is generally small (a few millivolts from a cassette or CD input or a
few microvolts from an antenna) and needs to be amplified sufficiently to operate an output
device (speaker or other power handling device). In small signal amplifiers, the main factors
are usually amplification linearity and magnitude of gain, since signal voltage and current are
small in a small-signal amplifier, the amount of power-handling capacity and power efficiency
are of little concern. A voltage amplifier provides voltage amplification primarily to increase
the voltage of the input signal. Large-signal or power amplifiers, on the other hand, primarily
provide sufficient power to an output load to drive a speaker or other power device, typically
a few watts to tens of watts. In the present chapter, we concentrate on those amplifier circuits
used to handle large-voltage signals at moderate to high current levels. The main features of
a large-signal amplifier are the circuit's power efficiency, the maximum amount of power that
the circuit is capable of handling, and the impedance matching to the output device. One
method used to categorize amplifiers is by class. Basically, amplifier classes represent the
amount the output signal varies over one cycle of operation for a full cycle of input signal. A
brief description of amplifier classes is provided next.
Block diagram of a typical op-amp – characteristics of ideal and practical op-amp - parameters of opamp – inverting and non-inverting amplifier configurations - frequency response - circuit stability.
Power Amplifier circuits.
Output stages of types of power amplifier (class A, class B, class AB, class C, class D)
Distortions( Harmonic and Crossover).
Push-pull amplifier with and without transformer.
Complimentary symmetry and Quasi- complimentary symmetry push pull amplifier.
Power Amplifiers: Classification of amplifiers, Class A power Amplifiers and their analysis, Harmonic Distortions,
Class B Push-pull amplifiers and their analysis, Complementary symmetry push pull amplifier, Class AB power
amplifier, Class-C power amplifier, Thermal stability and Heat sinks, Distortion in amplifiers.
Block diagram of a typical op-amp – characteristics of ideal and practical op-amp - parameters of opamp – inverting and non-inverting amplifier configurations - frequency response - circuit stability.
Power Amplifier circuits.
Output stages of types of power amplifier (class A, class B, class AB, class C, class D)
Distortions( Harmonic and Crossover).
Push-pull amplifier with and without transformer.
Complimentary symmetry and Quasi- complimentary symmetry push pull amplifier.
Power Amplifiers: Classification of amplifiers, Class A power Amplifiers and their analysis, Harmonic Distortions,
Class B Push-pull amplifiers and their analysis, Complementary symmetry push pull amplifier, Class AB power
amplifier, Class-C power amplifier, Thermal stability and Heat sinks, Distortion in amplifiers.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
TOP 10 B TECH COLLEGES IN JAIPUR 2024.pptxnikitacareer3
Looking for the best engineering colleges in Jaipur for 2024?
Check out our list of the top 10 B.Tech colleges to help you make the right choice for your future career!
1) MNIT
2) MANIPAL UNIV
3) LNMIIT
4) NIMS UNIV
5) JECRC
6) VIVEKANANDA GLOBAL UNIV
7) BIT JAIPUR
8) APEX UNIV
9) AMITY UNIV.
10) JNU
TO KNOW MORE ABOUT COLLEGES, FEES AND PLACEMENT, WATCH THE FULL VIDEO GIVEN BELOW ON "TOP 10 B TECH COLLEGES IN JAIPUR"
https://www.youtube.com/watch?v=vSNje0MBh7g
VISIT CAREER MANTRA PORTAL TO KNOW MORE ABOUT COLLEGES/UNIVERSITITES in Jaipur:
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Get all the information you need to plan your next steps in your medical career with Career Mantra!
https://careermantra.net/
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Water billing management system project report.pdfKamal Acharya
Our project entitled “Water Billing Management System” aims is to generate Water bill with all the charges and penalty. Manual system that is employed is extremely laborious and quite inadequate. It only makes the process more difficult and hard.
The aim of our project is to develop a system that is meant to partially computerize the work performed in the Water Board like generating monthly Water bill, record of consuming unit of water, store record of the customer and previous unpaid record.
We used HTML/PHP as front end and MYSQL as back end for developing our project. HTML is primarily a visual design environment. We can create a android application by designing the form and that make up the user interface. Adding android application code to the form and the objects such as buttons and text boxes on them and adding any required support code in additional modular.
MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software. It is a stable ,reliable and the powerful solution with the advanced features and advantages which are as follows: Data Security.MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
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A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
2. Induction of Power Amplifier
Power and Efficiency
Amplifier Classification
Basic Class A Amplifier
Transformer Coupled Class A Amplifier
3. Power amplifiers are used to deliver a relatively high amount
of power, usually to a low resistance load.
Typical load values range from 300W (for transmission
antennas) to 8W (for audio speaker).
Although these load values do not cover every possibility,
they do illustrate the fact that power amplifiers usually drive
low-resistance loads.
Typical output power rating of a power amplifier will be 1W
or higher.
Ideal power amplifier will deliver 100% of the power it draws
from the supply to load. In practice, this can never occur.
The reason for this is the fact that the components in the
amplifier will all dissipate some of the power that is being
drawn form the supply.
4. P1 = I1
2R1
P2 = I2
2R2
ICQ
RC
RE
R1
R2
VCC
I1
I2
ICC
PC = ICQ
2
RC
PT = ITQ
2
RT
PE = IEQ
2
RE
IEQ
The total amount of power
being dissipated by the
amplifier, Ptot , is
Ptot = P1 + P2 + PC + PT + PE
The difference between this
total value and the total power
being drawn from the supply is
the power that actually goes to
the load – i.e. output power.
Amplifier Efficiency h
5. A figure of merit for the power amplifier is its efficiency, h .
Efficiency ( h ) of an amplifier is defined as the ratio of ac
output power (power delivered to load) to dc input power .
By formula :
As we will see, certain amplifier configurations have much
higher efficiency ratings than others.
This is primary consideration when deciding which type of
power amplifier to use for a specific application.
Amplifier Classifications
%
100
)
(
)
(
%
100
dc
P
ac
P
power
input
dc
power
output
ac
i
o
h
6. Power amplifiers are classified according to the
percent of time that collector current is nonzero.
The amount the output signal varies over one cycle
of operation for a full cycle of input signal.
vin vout
Av Class-A
vin vout
Av Class-B
vin vout
Av Class-C
7. The maximum theoretical efficiency ratings
of class-A, B, and C amplifiers are:
Amplifier Maximum Theoretical
Efficiency, hmax
Class A 25%
Class B 78.5%
Class C 99%
8. output waveform same shape input waveform +
phase shift.
The collector current is nonzero 100% of the time.
inefficient, since even with zero input signal, ICQ
is nonzero
(i.e. transistor dissipates power in the rest, or
quiescent, condition)
vin vout
Av
11. Previous figure shows an example of a
sinusoidal input and the resulting collector
current at the output.
The current, ICQ , is usually set to be in the
center of the ac load line. Why?
(DC and AC analyses discussed in previous
sessions)
12. RC
+VCC
RE
R1
R2
RL
vin
ICQ
I1
ICC
The total dc power, Pi(dc) , that an
amplifier draws from the power
supply :
CC
CC
i
I
V
dc
P
)
(
1
I
I
I CQ
CC
CQ
CC
I
I )
( 1
I
ICQ
CQ
CC
i
I
V
dc
P
)
(
Note that this equation is valid for most amplifier power analyses.
We can rewrite for the above equation for the ideal amplifier as
CQ
CEQ
i
I
V
dc
P 2
)
(
13. R1//R2
vce
vin
vo
ic
RC
//RL
rC
AC output (or load) power, Po(ac)
Above equations can be used to
calculate the maximum possible
value of ac load power. HOW??
L
rms
o
rms
o
rms
c
o
R
v
v
i
ac
P
2
)
(
)
(
)
(
)
(
Disadvantage of using class-A amplifiers is the fact that their
efficiency ratings are so low, hmax 25% .
Why?? A majority of the power that is drawn from the supply by a
class-A amplifier is used up by the amplifier itself.
Class-B Amplifier
14. IC
(mA)
VCE
VCE(off) = VCC
IC(sat) = VCC/(RC+RE)
DC Load Line
IC
VCE
IC(sat) = ICQ + (VCEQ/rC)
VCE(off) = VCEQ + ICQrC
ac load line
IC
VCE
Q - point
ac load line
dc load line
L
PP
CQ
CEQ
CQ
CEQ
o
R
V
I
V
I
V
ac
P
8
2
1
2
2
)
(
2
%
25
%
100
2
2
1
%
100
)
(
)
(
CQ
CEQ
CQ
CEQ
dc
i
ac
o
I
V
I
V
P
P
h
15.
16. Calculate the input power [Pi(dc)], output power [Po(ac)],
and efficiency [h] of the amplifier circuit for an input
voltage that results in a base current of 10mA peak.
RC
RB
+VCC
= 20V
IC
Vi
25
20
k
1
Vo
)
%
5
.
6
%
100
6
.
9
)
48
.
0
)(
20
(
625
.
0
)
20
(
2
10
250
2
250
)
10
(
25
20
1
1000
20
20
4
.
10
)
20
)(
48
.
0
(
20
48
.
0
5
.
482
)
3
.
19
(
25
3
.
19
1
7
.
0
20
)
(
)
(
)
(
2
3
2
)
(
)
(
)
(
)
(
)
(
)
(
dc
i
ac
o
CQ
CC
dc
i
C
peak
C
ac
o
C
CC
sat
c
B
P
P
W
A
V
I
V
P
W
A
R
I
P
peak
mA
peak
mA
I
I
V
V
V
A
mA
V
R
V
I
V
A
V
R
I
V
V
A
mA
mA
I
I
mA
k
V
V
R
V
V
I
peak
b
peak
C
CC
cutoff
CE
C
C
CC
CEQ
CQ
B
BE
CC
BQ
h
17. Input
+VCC
RE
R1
R2
RL
N1
:N2
Z2 = RL
Z1
A transformer-coupled class-A amplifier
uses a transformer to couple the output
signal from the amplifier to the load.
The relationship between the primary
and secondary values of voltage, current
and impedance are summarized as:
L
R
Z
Z
Z
N
N
I
I
V
V
N
N
1
2
1
2
2
1
1
2
2
1
2
1
N1, N2 = the number of turns in the primary and secondary
V1, V2 = the primary and secondary voltages
I1, I2 = the primary and secondary currents
Z1, Z2 = the primary and seconadary impedance ( Z2 = RL )
18. An important characteristic of the transformer is
the ability to produce a counter emf, or kick emf.
When an inductor experiences a rapid change in
supply voltage, it will produce a voltage with a
polarity that is opposite to the original voltage
polarity.
The counter emf is caused by the
electromagnetic field that surrounds the
inductor.