Below are some circuit errors that can occur when solving.

Error 149081

There is no path from the start terminal to the end terminal of at least one of the current sources which does not pass through another current source or no path exists.

If two current sources are connected in series then error 149081 will occur when solving because one of the current sources is redundant and not needed. Delete one of the current sources and reconnect the circuit.

Another case that causes this error is when every branch that connects to a common node in a circuit has a current source. This makes the circuit overdetermined.

The workaround is to replace one of the current sources with a direct connection. Magnet will determine the current of this connection from Kirchhoff's current law, which states that all currents entering or exiting a common node must sum up to zero. A common example is shown below with the workaround shown in the right image.

               Overdetermined Circuit                                             Workaround

Note that this error can also happen with coil objects that are not in a circuit but are set up in a situation that is analogous to the above circuit cases (Coils: error 149081). 

Error 149095

At least one circuit terminal is unconnected.

When terminals of circuit components (including placed coils) are left unconnected or dangling then error 149095 will be reported when solving.

The workaround for a placed unconnected coil is to connect it in series with a 0 Amp current source. Or a simpler alternative is to unplace the coil (i.e. drag it out of the circuit into the left pane), in which case it should by default become current driven with 0 A.

After the error has occurred, the solver log will report the unconnected terminal (but other unconnected terminals may still exist in the circuit). A script can be used to detect and report all unconnected terminals.

Error 149075 or 149109

The solver has encountered a non-physical situation in the problem specification. (error code 149075)

These errors are not exclusive to circuits and can be caused by other aspects of the model unrelated to the circuit. One example where the circuit can cause these errors is when the terminals of a voltage source are shorted to each other (error 149075 in 3D and error 149109 in 2D).

Another similar cause that leads to the error 149075 in 3D static or 3D transient solves is when an inductor is in parallel with a voltage source in the circuit. The resolution is to delete the inductor since there is no reason to have an inductor in parallel with a voltage source.

The error occurs because in a static context the inductor is essentially a short circuit and the voltage source imposes a voltage across the inductor which contradicts the 0 voltage of a short circuit. The first time instant of a transient solve is a static solve so that is why the error can also occur in a transient solve. In 2D no error occurs but result quantities will most likely show invalid values instead of numbers like "-nan(ind)" or "inf".