slug tuned inductor specification

[circuitmangler]

Just a question on how to interpret a specification for
a slug-tuned inductor which reads something like:
"+/- X uH". Does that mean that the range of inductance
from lowest value to highest value is 2X uH? This seems to
be the intuitive answer, but I just wanted to verify it.

Also, is there a way to compute the actual upper and lower
limits for a slug-tuned inductor just from its +/- value
and knowing the composition of the core? For instance,
does the relative permeability of the core basically determine
the ratio of the upper and lower inductance limits, or is
more complicated than that?

Thanks,

CM

 

[Warpspeed]

What sort of slug tuning are we talking about here. Is it an air wound RF coil with a threaded slug, or a low frequency gapped ferrite pot core with a slug ?

Your best bet is to get some data from the ferrite manufacturers. They list their products giving typical adjustment ranges. Quite often the slugs are colour coded so you get a fair choice of adjustment range for any particular size.

Philip's make a pretty good range, and so do TDK. Finding something in a catalogue is easy, actually getting one in your hand can be a whole lot more difficult.