wrote:
Hello,
in an old VFO project that I'd like to duplicate (seems easy and
stable enough for me), the inductors (2) are specified as a number of
turns on a 5mm former with
"purple core". Now I know what a 5mm former might be, but I surely
don't have any idea what a purple core is and how to recognize it on
my parts department :-)
Any info is appreciated, thanks in advance.

Francesco IZ8DWF

Some company in Europe that was popular with amateurs made ferrite or
iron-powder cores and color coded the mixes. Purple doesn't match the
color codes for Micro-Metals cores that are available in the US, so it's
not one of theirs (or it's an obscure one).

You may be able to figure out the inductance, and make the inductor some
other way. This takes away some of the 'easy', but it's at least a method.

If you can post the schematic and the operating frequency somewhere,
someone here may take a stab at suggesting an inductance.

Or wait and see if someone in Europe or with experience with European
parts gives you a response.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html