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I am using circuit lab to help learn some basic concepts, and I built this simple circuit:

Since the circuit is purely resistive I assumed that the voltage and current would be in phase, but I am seeing them separated by 180 degrees in the time domain simulation.

To quote http://electronicstheory.com/COURSES/ELECTRONICS/e101-31.htm

"One important point to keep in mind, is that when current flows through a purely resistive circuit, the voltage and current arrive at the same point at the same time. In other words, Voltage and Current are in phase in a purely resistive circuit."

I had understood you need an element with reactance to change the phase of current or voltage, what am I misunderstanding here?

Thanks :)

Hi safire,

Welcome to CL.

You are probing the voltage V(x) which is the voltage across the voltage source, V1.

The current you are probing is I(V1.nA) which is the current through the voltage source V1.

I(V1.nA) is flowing out of V1 into R1 and so appears negative, i.e. 180 degrees out of phase with V(x).

If you hover over - and then click on the grey disc that appears at - the left hand end of R1 you can probe I(R1.nB) which will then appear in the right phase when you run the sim.

What you have encountered is the difference between measuring the current flowing into and that flowing out of a component.

For info: You have labelled the ground net as "y". Whilst you can do this, it is not necessary to put a net name on the ground net. CL already understands that it is 0V.

:)

Thanks Signality!

I see now that, if I for example put two resistors in series, that the phase of V and I are in phase on their both of their left hand inputs. I did not realize there would be an inversion of polarity depending on which side I measured at.