23 May
2005
23 May
'05
8:12 a.m.
Subject: Re: small valves
From: Tom Jennings <tomj at wps.com>
Date: Mon, 23 May 2005 00:20:47 -0700 (PDT)
To:
Cc: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
One word: hysteresis.
It is the one thing that makes it possible.
I bought a few hundred thousand new/unused plain cores
on ePay a
few years ago, for about twenty bucks. The problem is they're
about .005" OD! If you're going to make your own at home without
slave labor to go blind for you, you'll probably want cores large
enough to handle.
You supplied me some once. I was able to assemble a 4word by 8 bit
mat but I've not had time to actually drive it. Took two tries to
make it. The wire used must have a insulation that is nick resistant.
If you just want to play and make a 4 x 4 core or
something, I
wonder if you couldn't get decent hysteresis with some other
ferrite product. You could compensate for a "poor" core with good
electronics and/or brute force. I haven't looked at a toroid spec
sheet in ages and not for hysteresis.
I use a lot of the F and FT series torids down the .125" and
never saw any spec for hysteresis and I suspect sing most are
not easily saturable that would be the difficulty with them.
However tehy make near ideal transformeers at 100mhz!
Allison