Surprisingly simple push pull buffer

Yeah, that's what I'd have thought, too. But really, they are called "butte"s here in this area even without a flat top. And they often aren't all that large, surface area wise. Often just a bump, really.

I listed actual names. If you google them and take a look, I think you will see, for example, that Kelly Butte doesn't look flat at all.

In my case, Zion Hill does have a kind of flat top to it. But just north of me, on Tower Hill, there's less flatness.

Seems no real rule in play. More like people use hill, or butte, or whatnot to fit the other part of the name. For example, "Rocky Hill" sounds too much like a description than a name. So it gets called "Rocky Butte," instead. Then it sounds like a place. Etc.

Now if engineers got involved in defining things, I'm sure there would be more sense to all this. ;)

Yeah. But I like to know the exact angle. :) With Mt. Hood ever in presence, I always know pretty much exacty where I'm at all of the time.

I also like having these when I'm flying. Never need to look at instruments much. Always know my altitude and position, all of it exactly relative to the landmass, without even a conscious glance. It's always in mind all the time.

It is just strange to me that an "interstate", out of which I am pretty sure my fed dollars paid almost ALL of, gets permanent tolls.

Okay. It's just strange, period. We just don't do permanent tolls, out here.

No, everything toll-wise about everywhere east of the Rockies drives me nuts. You are right -- I'd see a toll one way, not another. And I began to wonder about "strategies" to avoid the darned things.

I don't mind you locals paying your local tolls. You know the territory and can figure the game out for yourselves. But to us born in Oregon types, it's crazy-making. I'm not entirely sure, but I have decided to travel a LOT LESS out that way partly because it isn't all that interesting (flat and unchanging for nearly forever) but also partly because the roadways are totally confusing.

Tolls on huge 4 and 6-lane highways??? What kind of sense is that?? And then on little things, too, in places I'd never expect. One darned well needs a MAP to figure things out. No sense to it. Just where ever some politician could figure out a place to line pockets, is all I can figure. Seems random.

Well, here they actually PULL them out. We don't do the slight of hand crap. Could. But I don't think politicians here would survive the attempt.

Hehe. No question about Illinois. Anyway, the name is Paul Powell. Look him up. And use "shoe box" too.

Interesting note. In those days in Illinois, to pay for your license you didn't write a check to the "Secretary of State" or to some department of motor vehicles. Instead, you wrote "Paul Powell." In fact, if you wrote the check out to "Paul Powell, Secy of State" the check would be refused or sent back uncashed and you wouldn't get the license. It had to be made out to his name and his name, only. Nothing more. It had to be personalized and have no earmarks of officialdom on it or else they wouldn't accept it.

Jon

I spent a bunch of time in Madison, helping Imago Scientific get going. Tragic story, in the end, but I enjoyed it back then. Nice place, nice people, decent coffee, good cheap beer at the student union on the lake. Been inside the Capital building? Nice stone.

The geology here is young. I don't know when Castle Peak was formed, but nearby Mt Pluto, which is now the top of the Northstar ski area, blew up and formed Lake Tahoe about 2 million years ago. There's tons of obvious glaciation here, with huge "eccentric" boulders scattered all over.

ftp://jjlarkin.lmi.net/PCT_Boulders.jpg

Califiornia is still rough and raw, unfinished.

John

"John Larkin" wrote in message news: snipped-for-privacy@4ax.com...

We have a few of those laying around. Which I suppose makes them relatively more "erratic".

Chamberlin went to Beloit a long time ago. Darn, they recently demolished the Chamberlin Science Building on campus -- they put in a brand new "green" science building, which looks nice and new and is spacious, though the shiny metal and glass is a bit conflicting with the traditional brick buildings on campus.

Tim

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Gee, I thought I invented that. It's nice to know there are others out there inventing this stuff too.

You can update it using a FET for the pull-down, and a schottky for the diode, which makes it faster and gets around Tim's Vsat concerns.

I understand the IRS21xx series are pretty rugged, but somehow I don't always fully trust an IC to be as tough as a good discrete circuit.

Joerg still does!

-- Cheers, James

to

Ts,

As Shakespeare said "the world is an R-C," but if you whip out the calculator you'll see that 1K and 25-ish pF (tau =3D 25nS) gets you through the switching zone more than quickly enough.

ice

The saturation voltage is lower than that, steady state, because it drops a lot when the output current falls.

I don't think I've seen a FET where even 0.8v from either rail would matter, but why would we drive a logic-level FET from 12v anyhow? If you define your need, then an optimum circuit can be designed. The LL FET constraint seems artificial.

Depends on exactly what you want to do, of course. All the realistic circuits have trade-offs, and the use's requirements dictate which tradeoffs you choose, right?

-- Cheers, James Arthur

On a sunny day (Sun, 15 Aug 2010 22:44:18 -0500) it happened "Tim Williams" wrote in :

HAHA, human made global warming melted that glacier I am sure. Must have been al the camp fires. LOL

Ah, but that only works for loads up to ~2500pF. Driving a hearty 10nF (>100nC) gate slows it right down.

You could also add a base-emitter resistor across the follower, to leak it down to nothingness, but that's really slow. It should be possible to get the last 0.5V in as much time as the rest!

Unfortunately, I haven't seen an SMT FET that is anything but LL. So if you want to use one of those complementary dual FETs as a half bridge (or two for H), you don't have any choice, other than tedious level-shifting.

Screw tradeoffs! I want awesome ;-)

Tim

Did you know that there is a mountain in Florida?

Space Mountain in Orlando doesn't count.

to

I'm not talking about an amusment park.

to

I've been on escalators way taller than Sugarloaf (95meters above sea level)

Don't we all, but "awesome" is relative. You don't want to build a dump truck to move a cupcake, right?

-- Cheers, James Arthur

I've heard of dense cake before, but neutronium is pushing it! ;^)

Tim

I grew up near a mountain in New Orleans. Monkey Hill, 12 feet above sea level.

John

How's the skiing?

John

Eccentric, erratic, whatever. Weirdo rocks.

John

That's how I like to design electronics: I want it all, and I want it fast and cheap. It annoys my employees, but once they are pushed, they usually go off and do it.

John

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I believe that's the length, not height. The longest are in Russia (100M) but this one isn't too shabby at 70m. it certainly was enough for my wife (she *hates* escalators).

"John Larkin" wrote in message news: snipped-for-privacy@4ax.com...

It helps when you consider "impossible" to be an absurdity.

Tim