What is a Feedback amplifier?
An electronic circuit that sends feedback from its output to its input to control and enhance performance is called a feedback amplifier. It works by taking a sample of the output signal, comparing it to the input signal, and then modifying the amplification process as necessary. Next, we will see the Block Diagram and Working of Feedback Amplifier.
Block Diagram and Working of Feedback Amplifier
Given Below is the Block Diagram of the Feedback Amplifier
The above block diagram consists of an amplifier and a feedback circuit.
Gain of amplifier is represented by A and feedback ratio is given by [Tex]\frac{Vo}{Vs} [/Tex]
The voltage feedback is given by ,[Tex] V_f= βV_o [/Tex].
For negative feedback :
[Tex]V_i=V_s−V_f=V_s−βV_o [/Tex]
For positive feedback :
[Tex]V_i=V_s+V_f=V_s+βV_o [/Tex]
Let’s consider the case of negative feedback,
The output voltage [Tex]V_o [/Tex] should be equal to [Tex]V_s−βV_o [/Tex] times gain of the amplifier “A”
[Tex]AV_s−AβV_o=V_o [/Tex]
[Tex]AV_s=V_o (1+Aβ) [/Tex]
[Tex]\frac{V_o}{V_s}=\frac{A}{1+A\beta\ } [/Tex]
Where [Tex]V_s [/Tex] is applied signal voltage.
The overall gain with feedback from the amplifier is,
[Tex]Af=\frac{V_o}{V_s} [/Tex]
Where [Tex]V_o [/Tex] is the output voltage and
[Tex]V_s [/Tex] is the input signal voltage.
The gain feedback for a positive feedback amplifier,
[Tex]Af=\frac{A}{1-A\beta\ } [/Tex]
And for a negative feedback amplifier,
[Tex]Af=\frac{A}{1+A\beta\ } [/Tex]
These are the standard equations to calculate the gain feedback of amplifiers depending on their type.
Feedback Amplifiers
A Feedback amplifier is a type of electronic Circuit Where the output of the Signal is fed back to the input. This feedback loop allows the Amplifier to adjust its performance according to the output received which helps to improve the characteristics of the signal. Feedback Amplifiers are used in various electronic circuits such as Operational amplifiers, audio amplifiers, and various other electronic circuits.
In this Article, We will be going through Feedback Amplifiers, We will start our Article with an introduction of the Feedback Amplifier, then we will go through its types and Topologies, At last we will conclude our Article with its Advantages, Disadvantages and Some FAQs.
Table of Content
- Feedback Amplifier
- Types
- Topologies
- Advantages
- Disadvantages
- Applications
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