"Watson A.Name -in message

Suppose that I have an inductor that's covered with epoxy or similar
that prevents me from seeing or finding out how many turns of wire are
on the core. The core is open, so that it's uncovered and most of the
magnetic field is outside outside of the inductor. Obviously it's a
bobbin type core.

I have measured the inductor with an inductance meter, so I know what
the inductance and other parameters are.

Suppose I take some wire, say roughly small if the inductor is small,
and wind it around the inductor, over the existing windings so that it's
within the magnetic field. I wind enough wire onto the inductor so that
I get about 1/9, or 1/16 or 1/25 the inductance in the new coil.


** One you have got that far you have constructed a transformer. Drive some
AC current into the original inductor's winding ( from an audio generator or
similar) and measure the AC voltage on it and on the overwind you created.

The turns ratio and the (unloaded) voltage ratio you measure are in exact
proportion.

The same method can be used to discover the number of turns in the windings
of a toroidal transformer or any transformer where you can place a small
overwind.



............. Phil