Written by shyam. Posted in Engineering on 04 April 2010.
Hot 3774 hits 0 favoured

INSTRUMENTATION AMPLIFIER

Circuit diagram:

 

gs

 

Theoretical explanation:

Differential amplifier with high input resistance is used in instrumentation amplifier. Its gain can be precisely set by an internal signal or external resistor. The high common mode rejection ratio makes this amplifier very useful in recovering a small signal buried in large common mode offers and noise.

The instrumentation amplifier is a closed loop device with carefully set gain. The instrumentation amplifier consists of two stages. The input first stage offers very high impedance to both input signals and allows setting gain with a single resistor. The second stage is a differential amplifier with output, negative feedback and ground connections are all brought out.

The input stage consists of two matched op amp. Each stage consists of two matched op amp. Each input V1 and V2 is applied to non inverting input terminal of its op amp. This op amp provides very high input resistance. The output of op amp is connected through a string of resistors.

The two resistors are R and Rg. Output voltage, Vo = (V2-V1) (1+2R/Rg)

Therefore decrease in value of Rg will increase the output voltage Vo. To increase in value of gain the value of Rg has to be decreased.

Advantages:

Even a small value of input voltage can be amplified using instrumentation amplifier.

Disadvantages:

For transmission purpose for long range, noise also gets superimposed along the original wave. Therefore specific cables are used to reduce noise.

 

 


shyam

Author: shyam

15 1814 0
  • No comments found
Powered by CjBlog

Latest Articles

The Chinese Government has, early this week, devalued its currency by 1-2%. This has caused surprise and shock in world capital and stock markets. The
The aim of writing this articles is to throw some light on a critical and less known topic called ' Lead poisoning'. I believe lead is silent killer because
Also known as the “City of Joy” and the “Cultural Hub of India”, Kolkata is amongst few cities in India to still retain its old world charm. Located

Categories

Related Articles

Indian soaps remind us of three things, high drama, lot of make-up and ever going on baseless elongated episodes. Most of us are bored to death by watching
We have to accept that the Television in houses acts a main role for all people. The real situation is that people will live even without food but not
T.V viewing is not a usual phenomenon, if we observe in counties like India where people spend their leisure time in it. As varieties of
The vast number of TV channels in English, Hindi and vernacular languages has brought a wide variety of programs into our drawing rooms. Today the viewer
Where would you find a precise explanation for what species of bird the Bank, Common and Jungle are? If you say it’s Myna, then you are either trying