fast divider?

I post information. When it doesn't inform people that you are a brilliant circuit designer, you feel insulted, though you should be used to that by now.

Many applications have well-defined trigger pulses. I certainly didn't spend any time "deliberately tuning" the circuit.

The trigger pulse has to be big enough and fast enough to turn off the normally-on transistor and push enough current into the timing capacitor to get the one-shot action, and the amplification is incidental to that.

You didn't recognise the circuit, couldn't see how it worked, and have been trying to deny this obvious point ever since. This isn't the kind of comment you like reading, and will claim that you are being insulted. Tough. This isn't some kind of mutual approbation society

Which is to say, to make a one-shot whose action you can understand

I'm sure you would.

The '121 chip is a better monostable, with a much more predictable and stable on time, though it is not retriggerable.

Current steering logic doesn't mess up the power rails anything like as much.

That circuit is in the 1964 GE Transistor Manual (7th edition, $2). Transistors used to be expensive so their use was minimized. Nowadays they cost about nothing.

I usually design circuits that I understand, but what matters is that they work.

With Spice or experiment, one can profitably design a circuit that you don't understand. I have a cool new sensor simulator circuit that I don't understand.

The SN74LVC1G123 seems to be the fastest official one-shot around. At

Just costs 30x as much.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Using a broad-band transistor in a classic circuit can give you a much shorter pulse. Broad-band transistors aren't all that cheap, and there aren't as many of them around as there used to be, but it can be a useful option.

You really don't want to. They have a nasty habit of doing something unexpected at inconvenient moments.

There was an ECL monostable that did a lot better. Sadly, it has gone obsolete. I did use it from time to time.

But they can give you a circuit that works, without messing up the rest of the assembly. Hunting for radio-frequency interference and stopping it getting at sensitive devices isn't all that enjoyable, and getting rid of it at source can be very attractive.

That's not a nasty habit, it's a talent that I practice and teach. Given an enormous space of undiscovered ideas, one profits from a method of exploring them in parallel with minimal filtering.

But inconvenient to who? Certainly not to me. Inventing things is fun and profitable.

It is an interesting question: does one understand then invent, or invent and then understand? Great scientific and practical ideas seem to be mostly invent or discover first, understand after.

The Plutonium book is full of examples.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

It's been said the steam engine did far more for engineering than engineering did for the steam engine.

Ditto thermodynamics.

Einstein's theories of relativity seem to be the rare case of predicting effects before they were observed, some decades before they could be demonstrated.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

The periodic table of elements is a usual example.

There were holes in it placeholders for elements or atomic species, later discovered.

The usual account since antiquity was that stringed musical instruments could be made reproducible their sound according to a theory of construction.

That physics or its science has got a ways ahead of the mathematics, still has that there are tons and tons of old-fashioned and considered obsolete the physics, for example "Faraday Rotation", that simply enough just need mathematics to bring them right back.

Otherwise though it's usual that only after the un-attainable sort of theoretical results of the fundamental physics of the 20'th century was it so that experiment can't explain itself.

The motive power of steam engines definitely made much for the study of aspects of the triple point of water, yet as well, accounts of pneumatics and the letter-tube delivery systems or even how a train locomotive makes its way up the tracks, for example from the World Factbook of 1846, make for theory meeting practice.

Here are some podcasts or video essays I recently recorded.

"Reading Foundations: double relativity" "Reading Foundations: continuous quanta"

Some books looked at include "The Grand Contraption" and "The Powers that Be".

Back to the idea of implementing a divider circuit, it's kind of funny that there isn't really a great example of an analog divider circuit that's sort of ideal and efficient, besides as for usual accounts of amplifiers and attenuators and so on. There are integrators and the like, accumulators, there's a place on the chart of ideal electrical components looking to be filled with a rational divider.

I started this thread about a frequency divider, namely divide-by-N, which can be done perfectly.

An analog divider is another thing entirely. Small denominators wreck things. Perfect isn't remotely possible.

I can't recall needing an analog divider in a long time, maybe never.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

That's a really nasty habit. Encouraging people to build circuits that can go wrong when they run into a situation that the designer hadn't expected is - to put it kindly - unwise.

But one you have "discovered" your original idea, you do need to explore it's ramifications in detail, and thoroughly understand how it works.

Sometimes. Getting a patent is an expensive process, as you'd know if you'd ever been involved, and it rarely pays off. When it does it can can pay off generously, but that doesn't happen often.

It can work both ways. One of my patents struck me as obvious, but I had to explain why it was obvious so often that I wrote it up a patent query to get out from under. I was a bit surprised when it ended up as patent. My father's 25 patents were all about stuff that he understood remarkably clearly, but other people hadn't noticed

It makes better stories than the tedious reality.

Einstein general relativity paper was published in 1915. and immediately explained the precession pf the orbit of Mercury, which had been inexplicable for a century or two.

Dirac's prediction of the existence of the positron preceded it's discovery by a couple of years. The magnetic monopole has proved more elusive.

There a perfectly good analogue four quadrant multiplier, now horribly expensive

Invention is precisely running into - running toward - the unexpected. Sometimes that's accidental, but can be deliberately provoked. Inventing needs the right skills and personality but improves with practice in the right environment. Books have been written about that.

Some people invent things. Some intelligent and (over)educated people actively resent invention, because they can't do it.

Understanding how it works is helpful but not mandatory. It is prudent to do the grunt work to make it economic and reliable; theory and understanding and simulation can help with those.

In the big picture, we never really understand how anything works.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Generously, one way of looking at a "test particle" in the standard narrative, not that there are any or they're "virtual", is that: that's a magnetic monopole, and they're pretty much "everywhere".

Then, the "skyrmions" and "spintronics" get involved, ....

People hear so much about magnets, and never electrets, ....

Go to Digikey and search for "electret".

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

That's a bizarre way of looking at it. It's doing something in a way that hasn't been done before, but it is goal directed, and you wouldn't start the process if you didn't have a pretty clear idea of what you wanted to do, if not exactly how you were going to do it.

None of them useful enough to have been touted at places that encouraged inventions and applying for patents. EMI Central Research was just such a place, and I worked there for three years without ever running into such a book. The histories of Bell Labs

didn't mention any such book either. People will write books with the flimsiest of justifications if they think the product will sell. Teaching people how to make genuine inventions would be a very good thing if you could do it, and a lot of confidence tricksters claim that they can. The evidence supporting such claims doesn't seem to exist.

I can't say that I've met any of them. My father and two of my friends have each got their names onto about 25 patents and none of them ever talked about people resenting that work.

At EMI Central Research we were encourage to submit patent queries. One of my colleagues put in a record number of patent queries - about fifty in one year - and was seen as having rather poor judgement. None of them turned into a patent. He would have benefited from better filtering.

It strikes me as absolutely essential.

Not so much prudent as essential.

You may not be able to manage that. Other people seem to do better.

Electrets are interesting. You can freeze a bunch of bound charge, so just inside the surface there’s a large E field.

Outside, there are conductors and free charge (e.g. air ions), so the field gets shielded out with distance. Eventually a layer of crud will collect, which will give ions a place to live.

Initially though, a clean surface is likely to have too low a density of states to neutralize the field completely, so it can persist out to a considerable distance.

I did an interesting front end for a semiconductor surface contamination sensor based on that—using a scanning capacitive probe, a small fraction of a monolayer of organic schmutz was easily visible from 200 microns away.

Cheers

Phil Hobbs

I strongly disagree; that is backwards. Sometimes we imagine products or circuits that nobody ever wanted or expected. It just happens sometimes at 2AM.

I have a folder full of ideas, most speculative and unexpected and probably dumb. We hire smart kids, college students, to explore them and write up a report on the possible uses, competitors specs and pricing, any interesting offshoots that occurr to them. They get a fixed fee when they turn in the report.

I have that one; good book.

Someone said that all the great inventions at Bell in those days were done by people who ate lunch with Harry Nyquist.

The real evidence is purchase orders.

The real evidence is purchase orders.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

It reminds of the similarities, and differences, of the "capacitor" and the "condenser".

These are basically ideal components, making advantage of that there are both the "electrodynamic" and "electrostatic", in effect, and about that things like a radio wave have both "very, very high" and "very, very low" frequency components, vis-a-vis the usual account of band, and about things like Faraday's law that makes that waves are always spirals and spirals are always waves, in nature.

So, much like the mythical "divider", and about for example ideas of constructing Fourier-style circuits including various what are often considered "uniqueness" results in mathematics that are actually "distinctness" results, many of these sorts components are readily available off-the-shelf, where they usually mostly gather dust.

It's kind of like the difference between "square wire" and "round wire" for motor windings: square wire gives better numbers.

So, any kind of application basically has an ideal electrical component, or rather, any kind of circuit is its own kind of ideal.

And very few of them look sensible after the sun has come up.

If you knew a bit more, it would be a much thinner folder.

An expensive self-indulgence.

People don't give you purchase orders for patents. They buy products. A good and patentable idea can be central to a product, but inept development can wreck the best of ideas. The Lintech electron beam tester was based on a patented idea of their boss, whose name was on the patent (which he'd got to own). He cheap-skated on the development to such an extent that one of his ex-engineers was able to build a pretty much identical machine which destroyed his business - nobody ordered a Lintech machine after the Schlumberger competitor hit the market, and after Lintech had delivered the last of the machine it had sold they went bankrupt. Mike Engelhart - of LTSpice fame - worked on that project.

It seems to be the only evidence you can understand. You seem to have got your name on exactly one patent, taken out by a group you were working with, so your grasp of what constitutes a patentable idea and what you can do with it does seem to be second hand.