dansawyeror wrote in
:

All,

This is a follow up to a dialog several months back on impedance
measurements. The question relates to smith charts and an HP 8407a with
a polar display. I was under the impression that the polar display and
the smith chart were pretty closely related. In fact hp made smith
chart
overlays for the screens.

The smith chart predicts a variable capacitor connected across a source
will be represented by an impedance semicircle in the capacitive
domain,
one of the points on the semicircle passes through the 50 ohm center. I
would expect to be able to create this using the 8407.

The 50 ohm centre is on the R=50 circle and the X=0 arc (which is
infinitely large in radius, so it is the the diameter from R=0
R=infinity).

Sit down and plot a few values of Z00+jx on a Smith chart, aren't they
all on the outside edge of the chart (the R=0 circle).

Owen