ehsjr wrote:
Joerg wrote:
ehsjr wrote:
You call that a coil? That's not a coil.
*This* is a coil!
No, it's a petunia. Or whatever. (I am not a botanical expert)
So, what's that super-stretch edition of coil for?
For a permeability tuned oscillator. It's an experiment to
measure water level, which changes only 3 feet nominal at
the site.
The finished coil is 42" of wire on 46" of PVC. A float
makes the coil ride up and down on a galvanized rod as
the water level changes.
It is accurate to within an inch, with +/- 3" being acceptable,
so that part is good. There is a big (ie 3" change in reading
with a 30F change in ambient) temperature problem to be solved,
but I ran out of warm weather to work on it. Looking for +/- 3"
accuracy between 50 and 100 F.
Can't you run some additional DC through the coil and regulate that so
you get a constant DC resistance through the coil?
--
Regards, Joerg
http://www.analogconsultants.com/