1. AMPLIFIER 2. PARTS OF AMPLIFIER 3. AMPLIFIER TYPES 4. OPERATIONAL AMPLIFIER 5. CLASSES OF AMPLIFIER 6. ADVANTAGES OF AMPLIFIER 7. USES OF AMPLIFIER

1. GROUP MEMBER’S:
Zeeshan Shabbir
M. Bilal
Fiaz Ashraf
Talha Zameer
Umair Ali
Hammad Hassan

2. 1. AMPLIFIER
2. PARTS OF AMPLIFIER
3. AMPLIFIER TYPES
4. OPERATIONAL AMPLIFIER
5. CLASSES OF AMPLIFIER
6. ADVANTAGES OF AMPLIFIER
7. USES OF AMPLIFIER

3. 1. AMPLIFIER………………………………………………………Zeeshan Shabbir
2. PARTS OF AMPLIFIER…………………………………………..M. Bilal
3. AMPLIFIER TYPES……………………………………………...FiazAshraf
4. OPERATIONAL AMPLIFIER……………………………………Talha Zameer
5. CLASSES OF AMPLIFIER…………………………………….…UmairAli
6. ADVANTAGES OF AMPLIFIER…………………………………Hammad Hassan
7. USES OF AMPLIFIER……………………………………....................................

4. Zeeshan Shabbir

5. An Amplifier is an electronic device that increases the power of a signal. It does this by taking energy
from a power supply and controlling the output to match the input signal shape but with a larger amplitude.
In this sense, an amplifier modulates the output of the power supply. The output signal is more than input
signal.

6. The amplification process is similar to the way in which the human receives the sound from our
surrounding. Sound waves will be sent through a microphone. The diaphragm of the microphone moves it
in a peculiar motion and converts it into electrical signals. This fluctuating electric signal will be
represented as compressions and rarefactions of the original sound. The electric signal will be encoded by
the recorder and stored in a tape, CD and so on.

8. Step 1:
In this setup the amplifier’s output circuit is connected to the emitter & the collector. The output circuit connects to the
emitter & the base.
Step 2:
When no current flow through the input circuit, free electrons from the n-type material fill the available holes in the p-type
material.
Step 3:
This create depletion zone (area where current can’t flow easily) at the boundaries bw the n-type layers & the p-type layers.
Step 4:
When current flows across the input circuit, it cause an extra voltage boost at the base electrode. This gets electrons moving
again, shrinking the depletion zone. Electrical resistance drops & electrons can move from the emitter to the collector again.
In this way the voltage at the base electrode determines the overall resistance of the transistor & therefore the current in the
output signal.

9. M. Bilal

10. Transistor
Resistor
Diode

11. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.
It is composed of semiconductor material with at least three terminals for connection to an external circuit.
NPN Transistor: PNP Transistor:

12. A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit
element.

13. The most common function of a diode is to allow an electric current to pass in one direction (called the
diode's forward direction), while blocking current in the opposite direction (the reverse direction).

14. Fiaz Ashraf

15. The four basic types of amplifiers are as follows:
Voltage amplifier:
Current amplifier:
Transconductance amplifier:
Transresistance amplifier:

16. Voltage amplifier:
This is the most common type of amplifier. An input voltage is amplified to a larger output voltage. The
amplifier's input impedance is high and the output impedance is low.

17. Current amplifier:
This amplifier changes an input current to a larger output current. The amplifier's input impedance is low
and the output impedance is high.

18. Transconductance amplifier:
This amplifier responds to a changing input voltage by delivering a related changing output current.

19. Transresistance amplifier:
This amplifier responds to a changing input current by delivering a related changing output voltage. Other
names for the device are transimpedance amplifier and current-to-voltage converter.

20. Talha Zameer

21. Operational amplifiers can be used to perform mathematical operations on voltage signals such as
inversion, addition, subtraction, integration, differentiation, and multiplication by a constant.
Operational amplifier is used to amplify DC and AC signals.

22. Negative Feedback is the process of "feeding back" a fraction of the output signal back to the input, but to
make the feedback negative, we must feed it back to the negative or "inverting input" terminal of the op-amp
using an external Feedback Resistor called Rƒ.
This feedback connection between the output and the inverting input terminal forces the differential input
voltage towards zero
This effect produces a closed loop circuit to the amplifier resulting in the gain of the amplifier now being
called its Closed-loop Gain.

23. +
-
VL
Gain (A) RL
Rs
Vs
Source Amplifier load
Ideally the output voltage is amplified version of the
source or
VL = A. Vs

24. Umair Ali

25. Amplifier Classes is the term used to differentiate between the different amplifier types.
The most commonly constructed amplifier classes are those that are used as audio amplifiers, mainly
class A, B, AB and C and to keep things simple, it is these types of amplifier classes we will look at here in
more detail.

26. Class A
Class B
Class AB
Class C

27. 100% of the input signal is used (conduction angle Θ = 360°). The active element remains conducting all of
the time.

28. 50% of the input signal is used (Θ = 180°); the active element carries current half of each cycle, and is
turned off for the other half.

29. As its name suggests, the Class AB Amplifier is a combination of the “Class A” and the “Class B” type
amplifiers
Class AB is intermediate between class A and B, the two active elements conduct more than half of the
time.

30. A class C amplifier conducts for less than 180.
Class C amplifiers are used extensively in radio communications
circuits.

31. Hammad Hassan

32. Despite the complexity involved, a properly designed class D amplifier offers the following benefits:
◦ Reduction in size and weight of the amplifier,
◦ Reduced power waste as heat dissipation and hence smaller (or no) heat sinks,
◦ Reduction in cost due to smaller heat sink and compact circuitry,
◦ Very high power conversion efficiency, usually above 90% above one quarter of the amplifier's
maximum power, and around 50% at low power levels.

33. Home Theatre systems:

34. Mobile phones: The internal loudspeaker is driven by up to 1 W.

35. Powered speakers: Powered speakers, also known as self-powered speakers and active speakers, are
loudspeakers that have built-in amplifiers.

36. High-end audio:

37. Bass amplifiers: Bass instrument amplification, used for the bass guitar, double bass and similar
instruments.

38. Sound Reinforcement: A sound reinforcement system is the combination of microphones, signal
processors, amplifiers, and loudspeakers that makes live or pre-recorded sounds louder and may also
distribute those sounds to a larger or more distant audience

39. Active subwoofers: A subwoofer (or sub) is a woofer, or a complete loudspeaker, which is dedicated to the
reproduction of low-pitched audio frequencies known as bass.