[GreenKeys] What ever happened to "Pot Cores"?

[hwhall at compuserve.com]

Messed around a very little a long time ago with some pot cores extracted from some kind of telephone filter units obtained surplus (think they might have been part of some MUX gear). They had air gaps in the center 'pin' with a little screwdriver adjustable ferrite slug that went into that gap for fine-tuning. Seemed like a good thing to build with at the time but then it seemed everyone was working with toroids instead so I dropped the tinkering.

WayneWB4OGM

-----Original Message-----
From: Harold Hallikainen <harold at w6iwi.org>
To: greenkeys at mailman.qth.net
Sent: Sun, Jan 24, 2021 8:31 pm
Subject: Re: [GreenKeys] What ever happened to "Pot Cores"?

I believe pot cores are still used in switching power supplies. They are a
lot easier to wind than toroids since the windings are on a small plastic
bobbin. The center pin length can also be adjusted in manufacturing to add
a specific magnetic gap to reduce the chance of core saturation. There is
also a small gap around the outside of the core. These gaps vary in length
with the amount of pressure holding the two sides together. As this
pressure varies with age, the inductance can vary.

But, other than that, I don't know about use of pot cores in audio filters!

Harold
https://w6iwi.org


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