AC circuit simulation not working

i have been building DC circuits to check currents and voltages no issues. I am now trying to do the same with an AC voltage source and i cant see any voltages or currents? im sure its just something simple i am doing wrong.

i just want to build simple circuits with a couple resisters, Capacitors, inductors and measure different currents and voltges throughout the circuit

by Bleahy
September 17, 2025

For AC, or time varying sources, you use [Simulation] button, and then click [Time Domain], then fill the required informations, don't forget to "Add Expression" by clicking on your circuit to get the required points where you want the voltage (you can also use expressions), and finally click [Run Time Domain Simulation].

In you case, you can specify the Stop Time as 2m (for 2 millisecond), the step as 0.01m. Add expression by clicking at the node between AM3 and R6, as example, or by editing an expression like: I(R7.nB) * 1000 where I multiply by 1000 to "see" the small signal given the "scale" used by the graphic.

You could use [Frequency Domain] if you use capacitors or inductors, since those depends on the frequency of the signal reaching them.

by vanderghast
October 03, 2025
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1 Answer

Answer by vanderghast

An hand-held voltmeter can work for sinus-wave AC sources, but since the average voltage of such a wave is zero over a full period, the voltmeter uses a non-linear response (diode, averaging, and others) which is a result generally irrelevant even for a circuit with a minimum of complexity. (Using the results shown by the voltmeter, no frequency considerations, even possible Kirchoff's laws violations, etc.)

For time varying signal, you should use an oscilloscope, which you can reach, here, with the Time Domain Simulation, to get a GRAPH of the voltages through time.

+1 vote
by vanderghast
October 05, 2025
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