[volt-nuts] Anyone know how to make stable inductors?

[Ed Breya]

The method described in the document would not make an actual inductor - 
it apparently fools the 4-port machine by providing the equivalent 
signals that the inductance would have. You can avoid getting precision 
inductors, and just go with this method (which I think is pretty clever 
if it actually works), or just use precision capacitors - they will 
provide negative inductance readout, which can be used for checking, 
with a little math applied.

If the R-C bridge method works, it would provide a nice equivalent L 
over wide frequency range. I'll have to try it too. It should be easy 
enough to rig up for testing to see how it works, before committing to 
building any fancy precision versions.

A few years ago I made up a bunch of reference (1% - good enough for my 
needs) capacitors in decades and in 1.59... (5/pi) ratios that I use for 
checking test and fixture setups to confirm proper running of my HP4276. 
I have an excel table that lists the caps and the L and R equivalents at 
the main test frequencies. The 1.59... ratio ones allow for round number 
decade negative L values for convenience.

Ed