Even with my lovingly crafted explanation (Washington DC/Cincinattus), there was still significant confusion over what the hell a Smith chart actually is.
Part of the problem is that two of the axes are the same in certain directions and one isn't even printed on the chart anywhere.
So, here we go again. Ignore my ability to draw a line. It's just plain embarassing.
And the explanation*:
- Red marks a line of constant reactance. Anywhere on this line has the same value of Im[Impedance].
- Purple marks a circle of constant resistance. Anywhere on this line has the same value of Re[Impedance].
- Blue marks a line of constant distance along a wave path. All values on this blue line are equidistant from either a wave source or load.
- Green marks a circle of constant reflection.
Some of you may be thinking, "I'm not drunk enough to appreciate this." Some of the rest of you, however, may be asking, "is impedance really a function of both reflectance and distance?" Yes kids, it is. These axes may be constant in a DC analysis, but when doing sinusoidal steady state, impedance is most certainly a function of distance.
It's also a function of time, too, but play a similar trick here: we ignore it.
So there you go. The Smith Chart, brought to you by the best tracing and coloring skills this side of kindergarten.
* Yes, the explanations here are backwards from those given before. It turns out that I had my head so far up my ass that I was thinking in terms of the wrong dimensions. For example, a rectangular graph would have horizontal lines which illustrate different values of Y.
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