At the old times, it was the different engineering paradigm: design for the best performance whatever it takes. With the use of the well designed stuff we defeat all enemies so the power in the wall outlet will be completely free.
I don't watch TV or movies, and I am not subscribed for the cable.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
That goes back all the way to Caesar and the Romans. They clear-cut pretty much all of what's now Italy to build one armada after the other, thinking that'll make them own the world. It didn't and now the soil on all those mountains has eroded. Nothing big will grow there anymore.
This one's worth it. You can rent it at video places and watch it with friends that have a VCR. No idea whether it made it onto DVD. We have friends who said their (Greek Orthodox) wedding was an almost verbatim repeat of that story and we all laughed really hard because all of us had seen that movie. To this day the husband has refused to show us pictures of his baptism right before the wedding. Too embarrassing, he says.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
A quick estimate would assume that during the first interval, only the ferrite path stores energy. As it's ungapped permeability is a number or orders of magnitude higher than the compounded material, this is valid.
This duration can be derived from the B= Vt/NA equation.
deltaB = ( V . t ) / ( N . A )
deltaB= flux density change in Teslas ( 1T = 10,000gauss) V= Voltage applied across the inductor winding (volts) t= period of applied voltage (seconds) N= number turns in the coil A= physical cross-section (ferrite only) of the magnetic medium (meters^2)
If the applied voltage is unipolar and reset to ~zero, the period to saturation corresponds to a B value of between 0.3 and 0.4 T (.35 nominal), depending on material grade and temperature.
If the applied voltage is AC, the period of the ferrite operation will be for double this value, as the flux will swing from + to - saturation levels.
RL
My favorite old keyboard (it was a Burroughs, which should give a hint of its age) had keyswitches that moved a small magnet to saturate a core, which had two one-turn windings (looked like staples), one to excite and one to sense. It had great key feel...no mechanical damping or hysteresis like a buckling switch. Hall switches exist, too, but this was ... elegant.
I still have a little bag of the ferrite cores used in that kind of keyboard.
-- Regards, John Popelish
I once bought a raw keyboard at some surplus outfit - it was about 64 keys with an SPST switch for each; the switches were waay kewl - it had sets of quadfurcated contacts facing each other, but with a little plastic baffle molded into the key.
v----plastic thing _ | | contacts \\ | | / \\| |/ /| |\\ / |_| \\ | | | | | |
When you pressed the key, the baffle went down, wiping the contacts and letting their spring force push them together.
I hand-wired a matrix, drove it with a 6502, and used it on my Z-80 TV typewriter. ;-)
Cheers! Rich
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