function of Transistr &oscillators ,their 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