component swap

[obiwanjacobi]

I was just thinking - when laying out a board with a couple of LEDs with series resistors, if you could say that when a passive component is in series with another passive component you could swap them without any change to the electric properties of that circuit.

Is that true?

And if so, are there any CAD programs that allow that (I was in KiCad and that doesn't even have gate swapping - great disappointment)...?

Thoughts?

[IconicPCB]

If laying out according to a netlist.. source of netlist needs to be changed , netlist refreshed and then artwork generated.

[T3sl4co1l]

Yeah, you would have to have a "branchlist" instead -- provides freedom of series connections instead of parallel.  (A netlist provides freedom of parallel connections, instead of series.)

The netlist is most common because of our bias towards constant-voltage (branches in parallel) circuits and topologies, which ultimately is underlaid by asymmetries of physics (volts beget energy levels which are fixed by quantum effects; current begets only energy *rates*).

Strictly speaking, I suppose a more precise netlist would call out both branches and nodes.  PCB tools usually autogenerate this from placement (i.e., the ratsnest).  Some tools, I think, would be able to support that (e.g., Altium's From-Tos).

Conversely, a less precise, and much less useful, netlist would call out neither branches nor nodes...

Tim

[xygor]

You might not want to swap if e.g one of the component leads is connected to its case.