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What is Vo?

My attempt is nothing more than a guess, and I'm not sure if I'm right:

I think Vo is 0 because current can only flow in a closed loop. Since no current flows into the little "arm" from Vo to ground, the voltage across R2 is 0 and thus Vo = 0 volts. Is this correct?

Also, would this mean that the node at the bottom of this circuit is grounded because Vo = 0? Or would it only be a virtual ground?

enter image description here

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Indeed, you are correct about Vo = 0V because no current can flow through R2 and thus Vo is equal to GND.

Vo cannot be regarded as GND nor as virtual ground because there is an impedance between Vo and GND. True GND will not change if a circuit current changes. In this case however Vo will change if a current flows through R2 and Vo is therefore not identical to GND. Only in this single specific situation it happens to be at the same potential.

Virtual ground requires an active part that drives the virtual ground node in a circuit in such a way that it is kept at the same voltage potential as ground, which again isn't the case here.

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Yes, you are right.

Why not use a circuit simulator? It really helps to understand unusual circuits.

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Without any connection between the negative of the source and the GND symbol, you are correct.

The voltage at the point of interest w.r.t. the negative of the supply will be zero

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