This document summarizes the key differences between amplifiers and oscillators. It states that amplifiers are used to increase the intensity of a weak input signal using a DC power source, while oscillators generate their own output waveform and act as the signal source in a circuit using positive feedback and a DC power input. The document then provides more details on amplifiers, describing their basic block diagram and functions. It also discusses transistor amplifiers and their uses. For oscillators, it defines them as electronic circuits that generate AC waveforms of a particular frequency using positive feedback and a DC input to act as the signal source for other circuits. It provides examples of oscillator types and their typical applications.

1. UNIT -3
OSCILLATORS
PREPARED BY: A.K.KONKANI

2. Difference between Amplifier and Oscillators
 The crucial factor which differentiates Amplifier and Oscillator.
 The Amplifier is used as a multiplier circuit which is used for
increasing the intensity of weak signal.
 while the oscillator is used as a source in an electronic circuit. The
main use of oscillator is for waveform generation.
 Oscillator is another important circuit similar to amplifier in
electronic equipment.

3. Amplifier :
 Definition : An Amplifier is a circuit which amplifies the weak signal and raises the
amplitude of the signal

4. Basic block diagram :
 what can be inferred from the definition?
 It is completely fine that amplifier increases the
intensity or amplitude of the signal.
 It clearly means it supplies energy so, does
amplifier generate the energy of its own?
 The answer will be NO.
 An amplifier cannot generate the energy of its
own but for this purpose, it utilizes DC source

5. Function of an Amplifier
 An Amplifier is used repetitively in a circuit, because the
signal losses its intensity after travelling to a long distance.
 It uses negative feedback.
 The input is required for its operation ,it can not operate
without input.
 The generated signal can be periodic or non-periodic.

6. Transistor : A Transistor is a semiconductor device commonly used to
amplify or switch electronic signals.
n-p-n transistor p-n-p transistor

7.  Practically Used …………………
 As a Switch
 As an Amplifier
 For Realizing logic gates.
 Regulator(voltage, current or power)

8. Oscillator :
 An oscillator is a electronic circuit which generates the AC waveforms of a particular
frequency for providing source to an electronic circuit.
oscillator
Output
signal
Dc input power

9.  An oscillator is an electronic circuit which can generate waveforms
either sinusoidal or non-sinusoidal and acts as AC power source.
 An Oscillator is used only in the initial stage when the circuit requires
signal source.
 For this no input signal is given but d.c. power supply is required.
 It uses a positive feedback.
 The signal generated by it will be always periodic in nature.

10.  In fact oscillator is the amplifier with positive feedback in which no
input signal is given.
 Similar, to the amplifier, the oscillator also does not have its own
energy but using energy conversion it can generate the waveforms of
desired amplitude and frequency.
 The DC source connected to oscillator provides DC power to it; the
oscillator converts this DC power into AC power and generates
waveforms of definite frequency.

11.  The oscillator is available according to the need of frequency for a particular
application:
 Oscillators are widely used in radio transmitter and receiver, television
transmitter and receiver.
 For example, for audio frequency application the oscillator used will be
audio frequency oscillator. This is because the waveforms generated by it will
consist of audio frequencies.
 An RC oscillator is used to generate a Low Frequency signal, an
LC oscillator is used to generate a High Frequency signal, and an Op-Amp
based oscillator is used to generate a stable frequency.

12. Thank You