boost=20
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Back when i was still interested in TV the multipole ring magnets on the = neck=20 of the CRT were called "purity rings". The field strengths were small = and they=20 were used adjust the collimation of the three electron beams to go = through the=20 shadow mask in the right direction.
they
That's not what he was describing. He was describing small chokes biased towards saturation with a permanent magnet. Inductance dependent upon magnitude and direction of current. These are for the purpose I have described.
Typically 10uH at zero current rising to 50uH at 5A in the "forward" direction. In the reverse direction, inductance doesn't decrease by much, as the core is pretty much saturated already. IOW, "forward" amp-turns neutralize the permanent magnet bias, reverse amp turns augment it.
Interesting thing to model.
--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)
Yes, but there have been other "advances". E.g.,
(google will turn up a variety of other techniques which may/may not be suitable to particular recording technologies.)
The point is, 3 holes in the platter stack won't prevent someone who REALLY wants to find out what you're trying to hide...
I wonder how hot you would have to get the materials to cause the domains to collapse?
boost
they
the
I've posted this before...
Message-ID:
L = Lo/[1 + (I/IH)^2]
Lo = Inductance at zero current
IH = Current at which L falls to 1/2 of Lo
This was measured and modeled (by me) at Sperry/Honeywell Space Systems Division. Seems to work well everywhere I've tried it.
Just add some bias in the denominator term for "I" to account for either a current bias OR a magnetic bias. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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I love to cook with wine. Sometimes I even put it in the food.
boost
the
neck
they
the
Thanks, Jim, I'll play around with that. The function looks like it oughta be the right shape.
--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)
lineal
the
800,=20on=3Ddetail
Quick and easy solution, get the platters out and microwave them. Takes about 15 seconds, works like a bulk eraser, then melts them.
There were also 'Static Convergence Magnets' on the necks of Tri-Gun Color CRTs.
Early Monochrome CRTs had an adjustable magnet used as an 'Ion Trap'.
-- Greed is the root of all eBay.
The trick there was a "bent gun", pointing off axis, at a slight angle. The magnet realigned the beam so that electrons went straight down the middle. Ions didn't get deflected by the magnet, and just hit the neck wall more or less harmlessly.
But you knew that already :-)
--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)
Yes. I learned that in the '60s when replacing CRTs. :) (I was 13) Instructions were packed with each one explaining why you no longer needed the Ion Traps.
-- Greed is the root of all eBay.
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