In this script, we will discuss the most important topic of Operational Amplifier, we have already discussed this topic in another script

Now we will discuss

    • What is Virtual Ground?
    • Using Infinite Voltage Gain
    •  Importance of virtual ground in op-amp?
    • Application of Virtual Ground
    • Difference between Virtual Ground and Real Ground

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What is Virtual Ground?

In electronics, a node may have any value of current or voltage but physical implementations of a virtual ground will have limitations of current handling ability and a non-zero impedances which may have practical side effects. In op-amps, the term virtual ground means that the voltage at that particular node is almost equal to the ground voltage (0V). It is not physically connected to the ground. 




Using Infinite Voltage Gain

It is clear that an ideal op-amp will provide infinite voltage gain. For real op-amps also the gain will be very high such that we can consider it as infinite for solve purposes.

  • Gain = Vo/Vin
  • As the gain is infinite, Vin = 0
  • Vin = V2 – V1

In the above figure  V1 is connected to ground, so V1 = 0. Thus V2 also will be at ground potential.

  • V2 = 0


 Importance of virtual ground in op-amp?

We know virtual ground means that the voltage at that particular node is almost equal to ground voltage (0V). The virtual Ground concept is very useful in the analysis of an op-amp when negative feedback is employed. It will simply a lot of calculations and derivations.


Application of Virtual Ground

1) It will simply a lot of calculations and derivations.
2)It is provides useful practical circuit effects that would be difficult to achieve in other ways.
3)It makes Op Amp circuit analysis much easier


Difference between Virtual Ground and Real Ground

Virtual GroundReal Ground
1)It is a concept that is made for easy explanation and calculation purposes.1)It is a terminal that is physically connected to ground 
2)Voltage is approximately Zero2)Voltage is Zero
3)It is not an infinite current sink3)It is an infinite current sink
4)Not electrically connected to Ground                        

4)Electrically connected to Ground