Capacitors not removing DC component after new update.

Hello,

The circuit you've posted is not valid. The entire right side of the capacitor is floating and has no reference point. In PSpice, for example, this would result in an error — “floating net.” LTspice avoids the error by likely assigning some internal reference to the floating node. The simulation results are actually correct — no current flows, and no filtering occurs — because without a defined path to ground or a load, there's simply no circuit for the capacitor to act upon.

Vilem

What you say makes sense. However I have some followup questions. If I wanted to simulate the following circuit: If I connect an oscilloscope probe to Vo, wouldn't it be centered at 0V? Also something changed, since on v24.0.8 of LTSpice, the floating node had no DC component.

You're right to ask — this is an important detail that’s easy to overlook.

If you connect an oscilloscope probe to Vo in a real circuit, then yes, the signal will appear centered around 0 V because the probe (with its high input impedance, typically 1–10 MΩ) effectively provides a DC path to ground. That’s what allows the capacitor to block the DC component and the output to “float” to a proper AC-centered signal.

As for LTspice v24.0.8, I'm just a user myself, so I don't know exactly how the developers handled floating nodes in that version. But it seems the simulator may have implicitly assigned some weak reference, giving the appearance of correct DC blocking even without a defined load. In the newer versions, this behavior appears to have become more strict or realistic — if there's no DC path, the node floats as it would in reality.

To replicate real oscilloscope behavior in LTspice, you can add a large resistor (e.g., 10 MΩ) from R3 to ground. This simulates the effect of the oscilloscope's input impedance.

Thats a smar way to simlate it. Thank you