I'm working on an LTSpice simulation of the Theremax and was wondering if anyone has modeled the 42-IF110 in a Hartley oscillator configuration. From the data sheet the primary inductance is specified to be 360uH+/- 6% with the following turns. (in another post the inductance value was listed as a lower value maybe with the slug in a more operational position?)
1-2 (105), 2-3 (2), and 4-6 (3). The primary is 1-3 so I think that 107 turns corresponds to 360uH. If I assume that the inductance is proportional to the square of the turns that would mean that the inductance of the coil segment between 2 and 3 would be about .13uH and the secondary inductance would be about .29uH. These numbers seem too low and I think the simulation results create an oscillator output amplitude that is lower than that actually achieved in the circuit. I'm specifying the mutual inductance close to 1 (K L1 L2 L3 .99).
Also from what I have read, moving the slug modifies the inductance but I have not figured out if it also changes the mutual inductance.
Anyway, I hope that this isn't already on some forum and I missed it. Any insight or modeling advice would be greately appreciated.
Thanks in advance,