I get your point, but I don't think it is correct. You CANNOT 'accidently' make a breakthrough unless you pretty well know what you're talking about.
Your example for AGB is a point in case - do you think if I had been in my shed and accidently spilled some coffee I could have invented the phone??
Some insights and progress can and often is made by unintended or lucky things, but that's only helping or speeding it up. Myriad are the cases where you just missed something that would have brought you forward but had to find at a later stage. Same difference.
Jan
No, that's no helpful info at all. Cu thickness is not determined by country
of origin but by technical necessities. We see here another example of
this audio people "thicker==better" fetish.
Already 70u is seldom used, if at all for real power stages or inner
power planes for multilayers. Yes, I have counterexamples also, like
microwave substrates with 2 mm Cu or Al on the bottom side, but that is
more for thermal reasons and to make up for the bad properties of the
teflon prepregs (flows under pressure, bends easily, traces stick about
as good as an egg in a teflon pan, mechanical TC) or the brittleness
of an Al2O3 substrate. Making quality vias here is artwork.
You cannot mount 0603 class parts on a 100u metal layer. There would
be a lot of underetching; a 5 mil trace would be about as high as wide
nominally. In practice, the acid would eat away most of it from the sides.
The deeper you must etch, the more.
For my own experiments I use presensitized FR4 material from Bungard,
available from SEGOR-electronics GmbH, Berlin.
It is easy to produce clean 5 mil traces or micro-SO8 footprints. The mask is
usually "offset film" , produced by a local printer shop from .pdf.
And I love that double sided 0.5mm FR4 with 17u Cu. Ideal to make
stamp sized miniboards that can be soldered to a larger ground plane
for development. I have a whole library of regulators, oscillators, OpAmp stages etc.
If you lose pads, thicker copper would not hold them. It's underetching,
glue, roughness of the epoxy, not exceeding the fr4 glas temperature,
trying to lift the part b4 everything is liquid, pressure from soldering iron.
The new leadless solders sometimes require high temperatures. I then
add a little bit of low temp. solder, that makes it a lot easier. And do not use
tin pumps, just solder wick to remove the excess.
Also, preheating the board to 100°C on a hot plate helps a lot against
loss of heat via GND layers. And get a hot air solder station.
regards, Gerhard
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David is easily the most innovative and creative guy in the tube design world. Remember that he already had tube amps with switching supplies, screen drive, digital autobias, tube-FET gain cells, and direct coupled servo'd outputs in 1977!
His novel way of simulating an output transformer using switching methods is brilliant. Apparently he didn't content himself with doing something interesting 40 years ago.
I get your point Jan but I think your viewpoint lacks imagination.
Many years ago I remember putting a 1uF cap across a transformer secondary thinking it would somehow help the diodes switch more cleanly. I noticed that that sound was clearly better so assumed my hypothesis was substantiated - Years later I realised the cap was modifying the resonanse that is excited in the secondaries when the diodes switch off.
So despite my abysmal lack of knowledge at that time I accidentally stumbled across a design feature that - in a modified form - I still usefully use in all my designs.
"Chance favors the prepared mind."
An example that I'm personally familiar with: back in the '70s, a very smart solid state chemist in Japan had a student from Korea run a polymerization reaction. The student didn't fully understand the directions and didn't have enough background or knowledge to know that when he ran the reaction, the catalyst concentrations were bizarrely too high. The reaction product was not expected, and the student went to the chemist with the odd-looking garbage to figure out what went wrong and why, and of course, how to dispose of the mess.
The Japanese chemist instantly recognized that, rather than things going wrong, the student had stumbled onto something new and interesting which appeared to be an organic metal. He showed the unexpected results to a visiting professor from the US (a very prominent solid state chemist) who further recognized what had happened. The two chemists got quite excited (the student was completely bemused!) and spent the next few years optimizing the reaction and getting higher purity.
Since neither of these chemists had extensive physics training, they were surprised that as the purity got better, the conductivity dropped. They were smart enough to consult a physicist at their university who explained band theory and doping in extrinsic semiconductors to them. He suggested that they try deliberate doping. When they did, the conductivity shot up to metallic levels.
The student was ready to throw out his mess. The two chemists and the physicist, the "prepared minds", knew better. The student got a nice publication for his resume and went on to a quiet, competent career. The "prepared minds", who recognized serendipity and had enough knowledge to sort things out properly, opened up a whole new field in chemistry and physics, with the consequent Nobel Prizes.
An example that I'm personally familiar with: back in the '70s, a very smart solid state chemist in Japan had a student from Korea run a polymerization reaction. The student didn't fully understand the directions and didn't have enough background or knowledge to know that when he ran the reaction, the catalyst concentrations were bizarrely too high. The reaction product was not expected, and the student went to the chemist with the odd-looking garbage to figure out what went wrong and why, and of course, how to dispose of the mess.
The Japanese chemist instantly recognized that, rather than things going wrong, the student had stumbled onto something new and interesting which appeared to be an organic metal. He showed the unexpected results to a visiting professor from the US (a very prominent solid state chemist) who further recognized what had happened. The two chemists got quite excited (the student was completely bemused!) and spent the next few years optimizing the reaction and getting higher purity.
Since neither of these chemists had extensive physics training, they were surprised that as the purity got better, the conductivity dropped. They were smart enough to consult a physicist at their university who explained band theory and doping in extrinsic semiconductors to them. He suggested that they try deliberate doping. When they did, the conductivity shot up to metallic levels.
The student was ready to throw out his mess. The two chemists and the physicist, the "prepared minds", knew better. The student got a nice publication for his resume and went on to a quiet, competent career. The "prepared minds", who recognized serendipity and had enough knowledge to sort things out properly, opened up a whole new field in chemistry and physics, with the consequent Nobel Prizes.
The Australian aboriginals did....their other invention is the boomerang...a hunting stick that comes back if it misses it's intended target ....quite clever actually !.
Dan.
Edit: The Aus version of the Atlatl is called a Woomera - http://en.wikipedia.org/wiki/Woomera_(spear-thrower)
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My point precisely. Humans have an amazing ability to make an observation, draw some conclusions, create something and then go onto refine it - without the use of differential equations, integration, trig, a science education or any body of prior knowledge. Fast loop innovation.
The boomerang is indeed an amazing prehistoric hunting tool.
I watched a Natgeo show a few years ago where they pegged the atlatl at about 20 000 years old. Any idea how old the boomerang is? It must be millennia as well.
The boomerang is indeed an amazing prehistoric hunting tool.
I watched a Natgeo show a few years ago where they pegged the atlatl at about 20 000 years old. Any idea how old the boomerang is? It must be millennia as well.
Yep, Pythagorus break through came after visiting Australia then known as Bump **** way down there..
Accidental break throughs are practically normal in science , uhh, ohh , yeah , i invented that...
A few :
http://m.youtube.com/watch?v=pf_Qv3q0M_c
Accidental break throughs are practically normal in science , uhh, ohh , yeah , i invented that...
A few :
http://m.youtube.com/watch?v=pf_Qv3q0M_c
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Wikipedia is not sure - Boomerang - Wikipedia, the free encyclopedia
Modern Aussies can be quite inventive/resourceful - Category:Australian inventions - Wikipedia, the free encyclopedia
Dan.
Thanks Dan for offering your insight.
For the record, I certainly don't put any 'blame' on Dimitri for doing the compilation of my internet comments. I don't remember even making them, or who opposed them, but I have been offering them to those who would listen, for about 25 years, now, even before the internet got popular, on a network called TAN. Dimitri just gathered them up, and did a very good job in organizing them into something understandable, when they started as a great number of individual inputs, at different times, and perhaps different locations. It is amazing that it is even readable. It is not easily readable by the novice engineer, I am told, and there is not much I can do about that.
For the record, I certainly don't put any 'blame' on Dimitri for doing the compilation of my internet comments. I don't remember even making them, or who opposed them, but I have been offering them to those who would listen, for about 25 years, now, even before the internet got popular, on a network called TAN. Dimitri just gathered them up, and did a very good job in organizing them into something understandable, when they started as a great number of individual inputs, at different times, and perhaps different locations. It is amazing that it is even readable. It is not easily readable by the novice engineer, I am told, and there is not much I can do about that.
Fellas, Please Stop Shooting The Messenger....
I applaud Dimitris selfless effort in compiling posts by JC, and for the
benefit of all.
I view this compilation http://jockohomo.net/data/johncurl-v.0.1.pdf akin to a fireside chat, and in such context, external input is actually unwelcome.
In this document, there is much information to read, understand and consider.
This includes discussion of problems that were new, back in the day, and
understandings and solutions that were found by collaborations of many, with JC
being one of the foremost pioneers.
Also included are wonderfully interesting snippets of audio history.
This document really is one of *Words Of Wisdom*, and if one is to read the
whole tome, he/she will be much the wiser for having doing so.
Just like all of the rest of us, JC will not be around forever, so best zip it
and listen up, while we have the chance.
Dan.
I applaud Dimitris selfless effort in compiling posts by JC, and for the
benefit of all.
I view this compilation http://jockohomo.net/data/johncurl-v.0.1.pdf akin to a fireside chat, and in such context, external input is actually unwelcome.
In this document, there is much information to read, understand and consider.
This includes discussion of problems that were new, back in the day, and
understandings and solutions that were found by collaborations of many, with JC
being one of the foremost pioneers.
Also included are wonderfully interesting snippets of audio history.
This document really is one of *Words Of Wisdom*, and if one is to read the
whole tome, he/she will be much the wiser for having doing so.
Just like all of the rest of us, JC will not be around forever, so best zip it
and listen up, while we have the chance.
Dan.
I got what I asked for..... what is the copper thickness being used in audio/video consumer gear out of Asia.
Besides the copper thickness, the glue or what ever it is which bonds the copper to the base material may be too low temp rated. But that is just a repair issue. I needed to know for an experiment I want to redo from years ago using thin copper pcb traces.
THx-RNMarsh
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