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Question
`What is meant by virtual ground in the op amp ?`
Question Submitted By :: Electronics-Communications
I also faced this Question!!     Answer Posted By

# 1
input resistance of the opamp is very high, so current is
cannot be flow through opamp and it passes through feedback
path. it create ground at input but it is not a actual
ground so we assume that it is virtual ground.

 Is This Answer Correct ? 117 Yes 36 No
Kishor Mahale

# 2
In an opamp the input impedance is very high because of the
first stage which is dual input balanced output differential
amplifier. Due to this, negligible current flows into the
opamp. This suggests that the potential difference across
the input impedance is zero and if any one terminal is
grounded then the potential at the other end is zero.
However it is called virtual ground as ordinary ground has
zero potential but can sink infinite current whereas virtual
ground has zero potential and can sink zero current.

 Is This Answer Correct ? 54 Yes 16 No
Sachin

# 3
we know that open loop gain of an ideal op-amp is
infinity.This implies that the differential voltage is
zero.That is, voltage at the inverting terminal=voltage at
the non inverting terminal.If the non inverting terminal is
grounded ,it means that the inverting terminal is
grounded.In other words there is a virtual short cicuit
between the two terminals.,but no current flows through it
since there is no physical connection between the two.This
is virtual ground in op amp.

 Is This Answer Correct ? 31 Yes 9 No
Shobha

# 4
since in an op amp the input resistance is very very high
so at the input node no current flows in to he opamp
and ,it passes through feed back resistance, so at the
input we assume virtual ground

 Is This Answer Correct ? 71 Yes 57 No
M.electronis

# 5
Since the resistance between inverting and non inverting
terminlas of op amplifier is very high. Therefore ideally
no current or very samll current can flow through these
termonals. if we model this we must have
I+ = 0 = I-
So this creats a ground which is not like the actual ground
but it is said to be the virtual ground.

 Is This Answer Correct ? 27 Yes 16 No
Azhar

# 6
input resistance of the opamp is very high, so current is
cannot be flow through opamp and it passes through feedback
path. it create ground at input but it is not a actual
ground so we assume that it is virtual ground.

 Is This Answer Correct ? 13 Yes 8 No
Moumita

# 7
Since an ideal amplifier has infinite input impedance so practically a very negligible voltage exist there and no current flows inside but it is actually an approximation in order to make calculation easier.It is called as virtual ground as it close to zero value so as actual ground is zero.....hope u got it
 Is This Answer Correct ? 4 Yes 0 No
Usama

# 8
as v know dat the input impedance of the opamp is ideally infinite.basically it means impedance between inverting and non-inverting terminals is very high.by this v can say that internally current passage between the terminals is ideally zero.basic concept here is current between two equal voltages is zero.using dis v can say dat voltages at two terminals are equalbcz current is zero.this is called virtual short.if any one terminal is grounded the other terminal is also grounded.simple very easy concept!!!!!!!!!!!!!!!!!!hope it helps:)

ur kedas!!!!!!!!!!!!!!!!!!!!!

 Is This Answer Correct ? 1 Yes 0 No
Kedas

# 9
To achieve a reasonable voltage at the output (and thus
equilibrium in the system), the output supplies the
inverting input (via the feedback network) with enough
voltage to reduce the potential difference between the
inputs to micro volts. The non-inverting (+) input of the
operational amplifier is grounded; therefore, its inverting
(-) input, although not connected to ground, will assume a
similar potential, becoming a virtual ground.

 Is This Answer Correct ? 1 Yes 1 No

# 10
since there are two input terminals in the inputside so the
resistance between the two input terminal is very very
high.so a negligible amount of current flows through op-amp
otherwise the current will be zero,then current only passes
through feedback resistance.hence the input terminal is
assumed to be virtual ground

 Is This Answer Correct ? 8 Yes 10 No
Safi Sara

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