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Trying to understand how CircuitLab measures DC voltages in the DC simulation. Things work as expected with a closed circuit. When I have an open circuit the voltage is the same before or after the load. In my example 12V, Vout vs Vin.

Thanks

https://www.circuitlab.com/circuit/azx2cekvwymx/open-circuit-voltages/

Hi @kubes! When SW1 is open circuit, then there is no current flowing through R1, and so no voltage drop across it. Therefore V(out) = V(in). Does that help?

The voltages are measured relative to your labeled ground, as is typical for this sort of software. If you want a relative voltage, you can explicitly do the subtraction by clicking "Add Expression".

Also see Labeling Voltages, Currents, and Nodes for more.