When I was much younger and harvested components from valve (tube) TVs & radios, pie-wound chokes were pretty common - and I added a decent number to my junk box.
Unfortunately, the exposed pie windings were vulnerable and none survived being in the junk box.
Just wondering whether anywhere still makes them?
The usual types were either wound on a hollow paxolin tube, or a high value resistor - one of those old carbon composition types cemented into a ceramic tube.
I read somewhere recently that they were still available, but I cant' remember where I read it, or where they were being sold.
The construction articles will specify "2.5mH", really quite large values, though every so often they'd specify only "1mH". That later seemed to be overkill, I wondered if it was one of those things where a value became familiar, and readily available, so it was self-perpetuating.
Generally, I don't think the moulded RFCs of more recent times (they look moninally like resistors, except a lighter color, but they do have color coding) are appreciably less components than the old pie wound ones, except maybe they don't get as large in value.
The problem now is that even the old scrap is hard to get, newer equipment with newer parts is what gets discarded. Good in lots of ways, but lousy if you need those old RF chokes or tube sockets.
Michael
Somewhere I have what could be a Philips EE kit 10mH RFC, the ones in all the kits I had were bare single pie chokes, most were dry but one was wax impregnated.
The one I came by more recently would be a later model as its resin dipped.
IIRC - the ballast in a CFL is usually a few mH, but probably not a lot of good for RF.
For what it's worth... Hammond still makes some 3-pi-wound RF inductors. Mouser stocks a few... from 1 mH up to 25 mH.
Thanks - its mostly out of curiosity, but handy to know should I happen to need some.
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