The orth concept in 2D geometry and graphics is where, given some vector, we find a vector (line) that is at right angles to the original. We have a tiny bit of choice about how to do it – we can pick a vector to the left, or to the right – but it’s very simple (more here).

The equivalent function in 3D is one of those odd little problems where you are given some freedom with the answer, and you don’t really care about that freedom – just pick something please! – but you’re made to care about it anyway and do what feels like too much thinking. Bah!¹

I want to mention the concept of walkabout and then go for a meander with the ohmaps idea. The idea is to eventually look at if the ohmap extends from resistance (DC behaviour circuits) to impedence (AC circuits) in any useful way.

I introduced ohmaps in parts 1 and 2 and looked at some simpler examples.

We looked at parallel and series resistor networks (and combinations of those):

And I wrote this:

And not every resistor network can be shown as an ohmap – things outwith simple series/parallel nestings, like delta or Y networks.

It turns out I was a little hasty here. So how might ohmaps cope with more interesting networks?