Written by shyam. Posted in Engineering on 04 April 2010.
Hot 4046 hits 0 favoured


Circuit diagram:




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.


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


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




Author: shyam

15 1814 0
  • No comments found
Powered by CjBlog

Latest Articles

Introduction  There is no denying the fact that endeavour and fortune make our dreams fulfilled. Yet we need confidence to accomplish our long-cherished
The recent terrorist attacks on French soil are an eye opener. The French capital was hit by a wave of attacks, that left over 130 people dead. The French
Birds-the symbol of love Most of us hear that there are thousand and one ways of loving in the world while some others feel there are as many ways of


Related Articles

After the December gang  rape in 2012 of a young girl in a moving bus in Delhi, an incensed public forced the government to amend the rape law. The
Jurisprudence all over the world recognizes rape as an offence. It means carnal knowledge of a woman against her will.In India the British enacted the
Rape is a crime that means carnal knowledge of a woman's body without her consent. In effect it means forcible sexual intercourse and subsequent gratification
What it really means  We see people fighting out litigations and law suits for various reasons - it could be because of property matters, criminal
Every edition of IPL has seen reports emerging of huge amounts of money gambled away on betting in India. This year the Delhi and Mumbai police have