4.2.7 OpenCircuit

Circuit element type OpenCircuit.

An open-circuit branch is essentially the same as an independent current source with zero source current. The value specification is ignored. However, it should be set to 0 (zero) to reflect the fact that the source current is zero. Note that open circuits are mostly used implicitly as controlling branches of voltage-controlled sources but they may also be used explicitly in a netlist when a voltage meter is needed. In the latter case, modified nodal analysis employs a special matrix fill-in pattern which augments the vector of unknown node voltages by the branch voltage across the open circuit. This allows for directly computing the differential voltage between two nodes neither of which is ground. Without the voltage sensor, two node voltages would have to be solved for and then subtracted from one another, which would be computationally more expensive.