small valves

[Allison]

>
>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