Electronics - Operational Amplifiers - Discussion

Data incomplete. Without knowing whether it is negative feedback or not. We can't say it is in the virtual ground!

In inverting amplifier, When the positive terminal is connected to ground, then the voltage (potential) between inverting and non inverting terminal is zero. So inverting input terminal should be virtual ground.

Data incomplete. Without knowing whether it is negative feedback or not. We can't say it is in virtual ground!

Op amp will force the differential voltage across the inputs to zero, the inverting input will also appear to be at ground. In fact, this node is often referred to as a virtual ground.

If the positive is grounded then why can't we take other terminal as virtually grounded?

Hence I think this is the answer.

I think, if the op amp is in virtual ground, there should be a negative feedback. Without feedback we can not say virtual ground concept.

Can you give me simple explanation?

An op amp can produce a signal which is 180 degrees out of phase (inverted) with respect to the input signal.To use an op amp as an inverting amplifier, you must send the signal into the negative input instead of the positive input. the op amp will do everything it possibly can to make the voltage (signal) on the the negative input match the positive input.The positive input is connected to ground.

It's shown as being connected through a resistor but the resistance to ground in unimportant. What is important is that the positive input has no signal (it's connected to the reference, ground). This means that the op amp's negative input will have no visible (voltage) signal on it. When you're driving the negative input it will act as a virtual ground.