EEVblog #833 - Mailbag

[Brumby]

I wasn't sure - so I posted on both.  Facebook first, then here.

My interest is educational:  A valve circuit that performs a useful function.  It's small, easily handled, easily stored and simple enough to fiddle with.

[gadget73]

Maybe it's using Cherenkov Radiation?

https://en.wikipedia.org/wiki/Cherenkov_radiation

I've been told it isn't, but having experienced both tube florescence and Cherenkov radiation personally, I can tell you its awful similar looking.   I have a number of tube amps, and some of them do have the blue glow if they run at high enough voltages.  I also work at a place that sterilizes things using a large amount of gamma radiation.  To "turn off" the system, the isotope is dropped into a pool of water, where it produces quite a strong Cherenkov glow. I'm in there at least once a month doing maintenance, sitting above that pool.  Its a pretty blue glow, but I'm glad its 20 odd feet down.



 For what it's worth, I've never been able to pick up any radiation from a vacuum tube on my Geiger counter.  Mine will pick up beta radiation too, if any was to be had. 

[Pentium100]

I've been told it isn't, but having experienced both tube florescence and Cherenkov radiation personally, I can tell you its awful similar looking.   I have a number of tube amps, and some of them do have the blue glow if they run at high enough voltages.

I do not think that the electrons in a vacuum tube have enough energy to produce x-rays. Tubes running at 10kV or higher voltages do produce x-rays, but not the regular tubes that run at 100-1000V.

So, it's probably just fluorescence of the glass and metal, I wonder how it would look like (that is, what the pattern would look like) if the inside of a tube glass was coated with phosphor.

[EEVblog]

Maybe it's using Cherenkov Radiation?
https://en.wikipedia.org/wiki/Cherenkov_radiation

That reminds, I have footage from the Australian Synchrotron form a few years back I haven't edited yet!

[EEVblog]

Dave, I invite you to believe that tubes are cool. Even though these days they are mostly connected to audiophools.
I would like to see a video ,like fundamentals friday, where you explain a little bit of theory of operation and build and
probe simple circuit with a tube. 

Perhaps.
I'd have to brush upon that one though, because I have never built nor worked on valve gear before.
I think I had Doug Ford explaining a valve mic amp front end in one of his videos?

[gadget73]

I've been told it isn't, but having experienced both tube florescence and Cherenkov radiation personally, I can tell you its awful similar looking.   I have a number of tube amps, and some of them do have the blue glow if they run at high enough voltages.

I do not think that the electrons in a vacuum tube have enough energy to produce x-rays. Tubes running at 10kV or higher voltages do produce x-rays, but not the regular tubes that run at 100-1000V.

So, it's probably just fluorescence of the glass and metal, I wonder how it would look like (that is, what the pattern would look like) if the inside of a tube glass was coated with phosphor.

Some of the high voltage rectifiers used on TV sets did kick out some X-ray, but those were usually 20kv or more.  I've seen some that had built-in lead shields on them.   I believe you are quite correct about lower voltage tubes though.  I've actually checked with my geiger counter but it has never read anything.   I suspect the coloration is more of a coincidence, not actually Cherenkov.  Both do look quite cool though.

[bktemp]

Some of the high voltage rectifiers used on TV sets did kick out some X-ray, but those were usually 20kv or more.  I've seen some that had built-in lead shields on them.   I believe you are quite correct about lower voltage tubes though.  I've actually checked with my geiger counter but it has never read anything.   I suspect the coloration is more of a coincidence, not actually Cherenkov.  Both do look quite cool though.

Many large colour tvs used a shunt regulator triode for stabilising the high voltage: When the screen displayed a less bright image, the regulator tube consumed the current to keep the voltage stable. Because it was connected to the full 20-30kV, it produced x-rays. The datasheets have x-ray warnings in them. In Europe PD500 and PD510 were the most common shunt regulator tubes. The PD510 was an improved version with better internal x-ray shielding. The Russian GP5 is still available today.
X-rays are beeing produced above a couple of kV, but the glass shields them until you go over 15kV.

I'd have to brush upon that one though, because I have never built nor worked on valve gear before.
I think I had Doug Ford explaining a valve mic amp front end in one of his videos?

Tubes are very similiar to jfets.
Even if most low voltage and low power tubes are obsolete, they are great for understanding the operation principle, because you can see all their elements even without disassembling it. So it is much easier to go from the theory with the electrons beeing controlled by the electrical to field to the practical demonstration on the actual device. Using a transistor you have to believe it works the way somebody tells you, because everything is too small to see and it is hidden inside an opaque case.

Most tubes do not need several 100V to operate. Some of them even work at 12V. The available current will be quite low and may be too low to do something usefull, but it should be enough for demonstrating the operating principle. Most tubes rated for higher currents (that means several 10mA for most tubes used in consumer products) will work better at low voltages than low current signal tubes, except for tubes specially designed for low voltage, low power battery powered products.

[SeanB]

CRT TV sets used a leaded glass as a front panel, to absorb the Xray production. As well the side glass was leaded, with a graded glass series dropping the lead concentration, so the expansion of the glass was spread out, to a standard glass for the gun assembly, and then another graded series of glass to make the pin area with all those dumet seals. Thus no xray radiationfrom a CRT.

The fluorescence of the glass is direct, caused by UV radiation produced in the tube from contaminants and stray gas. I see it on metal halide lamps on start up, where the glass outer quartz glows blue for a few seconds until it is overwhelmed by the light output of the main emission. There it is very visible, as you have 100W of initial UV light being blocked by the glass.

[Zucca]

Man I hate to do this, but it seems also Louis is lined up with Dave



...and all of this on Xmas. I mean God become a baby, a man in order for us to see and understand better what does it means. Sadly those reactions are pushing me to write this up.

In my POV there is a beautiful and deep relationship between "fatih" and "reason".
I am an happy Roman Catholic and I love science.

A quick suggestion for everybody (atheist or not), please do deeper in what you think it is the "Truth". There is no better way to live this life. Just use your reason at 100% (for me it is equal to faith at 100%, maybe brain at 100%= Heart at 100%?). I hope for everybody that "God" or "Atheist" is a beautiful starting point not the "job done" one.

A quick suggestion for Christian people: if you can't provide a concrete reason don't shoot out there things like "you need to believe because you need to believe" or "We need to follow God and I all I can give you are smokey unclear reasons". Christ is a Men in flesh not a theory. Stay with your foot on the ground don't become like "Ned Flanders" in the Simpson. And also please stop to try to convert people, first live your faith and the conversion jazz will take care for itself without any extra effort. (To all who wrote those letters to Dave, I hope your intention was growing in your faith and not converting someone on youtube. Please don't take it personal it is just my point of view)

Finally there is (and will be) no objective proof or equation that tell God exists, like there is no objective evidence that girl is the wife (=will love you for the rest of your life) you are looking for. [BTW is a wife reasonable?] Just because love needs to be a free act, I mean between a "YES" or "NO" you say a free "YES" without any theory science bla bla... That's how love is and it is reasonable and so beautiful like this (thanks be to God).

Dave, if you can, please avoid to spoke about your atheist position putting a bad light of the other ones. That's why I give you a yellow card for using the word "Christmyth", but not worriers I already forgive you.

Merry Xams to you all!

PS: Sorry if I step over the line, I promise I will not do it again. Oh well, maybe on Xmas 2016  .

EDIT: Just found Dustin from SmarterEveryday who is thinking like me, that's cool!

https://www.youtube.com/watch?v=VvVigAr4hZc#t=7m14s

[Artlav]

For what it's worth, I've never been able to pick up any radiation from a vacuum tube on my Geiger counter.  Mine will pick up beta radiation too, if any was to be had.

Actually, the only radiation you can get from the valves is soft X-RAYs, which are mostly absorbed by the glass anyway.
For that, you need ones that run at high enough voltage.
Which is quite rare these days.
I talk about the effect here, including a video of the glow: http://www.ribbonfarm.com/2015/11/23/artisanal-hand-crafted-electrons

[all_repair]

Christmas always bring out religion discussion :-)

All the Darwinists need to look at religion from a functionality view than from their own Darwinism regilious view.  It is the best invention of mankind, when your muscle and neuron is near expiry, which would you choose - religion or Darwinism?
Not having a religion is no good for the society, and is very tough and very stressful for a lot of people that do not have the capacity to resolve the unknown, unequalness,  dissonance in life.  The biggest issue I think about religion, is a single-god religion.  It can be hj-jacked easily, and there is no way to stop the one upmanship in a single god religion.  And history has proven, the ultimate homage is the human sacrifice to prove your belief to the god.  And there is no other god to stop this madness.   The current human-bombing is an exact expression of the problem of a particular single-god religion.  From my Darwinist view, a multi-god construct is better than a no-god and a single-god construct.

[coppice]

Christmas always bring out religion discussion :-)

All the Darwinists need to look at religion from a functionality view than from their own Darwinism regilious view.  It is the best invention of mankind, when your muscle and neuron is near expiry, which would you choose - religion or Darwinism?
Not having a religion is no good for the society, and is very tough and very stressful for a lot of people that do not have the capacity to resolve the unknown, unequalness,  dissonance in life.  The biggest issue I think about religion, is a single-god religion.  It can be hj-jacked easily, and there is no way to stop the one upmanship in a single god religion.  And history has proven, the ultimate homage is the human sacrifice to prove your belief to the god.  And there is no other god to stop this madness.   The current human-bombing is an exact expression of the problem of a particular single-god religion.  From my Darwinist view, a multi-god construct is better than a no-god and a single-god construct.

Are you trying to say, in a long winded way, that you are pro-bullshit?

[TheUnnamedNewbie]

It is impossible to have a debate with a religious person. I mean this not in the "religious people are unreasonable and can thus not be reasoned with" way, but from the base idea of what a debate requires. To have a debate - a discussion where you use arguments to back your opinion/idea/... on a matter, you need to have something to build arguments atop of - a base (Kernel?) of axioms/statements which all parties involved agree upon as the "truth". It is here where the issue lies with debating about religion - as each religion (let us for the sake of simplicity add atheism to this list - I realize that it is not really a religion) has different "truth kernels". Some athiests might consider knowledge gained through the scientific method as basic truth, Christians might start from some part of the bible, I know people who believe in spiritual things that use the idea of everything is energy (and not in the sense of energy = work * time).... There is no point in arguing, because none of the parties will see the arguments of the others as valid since they don't accept the base truths these arguments are built upon as true.

Just a quick note: I don't want to go into the philosophy of knowing what is the most correct base truth or the argument that facts you get from the scientific method might be better/equal/worse than those from scriptures - Just want to point of the line of thought and why I no longer bother with religious debates)
I have often also thought about the fact that even though I live in a country where religion and politics are supposed to be separate, almost all of out public holidays are based of of christian festives/events, and I have been bothered by this face.

[Jacko]

The Cool Sound of Tubes:

http://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes

-Jacko

[all_repair]

Christmas always bring out religion discussion :-)

All the Darwinists need to look at religion from a functionality view than from their own Darwinism regilious view.  It is the best invention of mankind, when your muscle and neuron is near expiry, which would you choose - religion or Darwinism?
Not having a religion is no good for the society, and is very tough and very stressful for a lot of people that do not have the capacity to resolve the unknown, unequalness,  dissonance in life.  The biggest issue I think about religion, is a single-god religion.  It can be hj-jacked easily, and there is no way to stop the one upmanship in a single god religion.  And history has proven, the ultimate homage is the human sacrifice to prove your belief to the god.  And there is no other god to stop this madness.   The current human-bombing is an exact expression of the problem of a particular single-god religion.  From my Darwinist view, a multi-god construct is better than a no-god and a single-god construct.

Are you trying to say, in a long winded way, that you are pro-bullshit?

Pro or not pro is not the point.  From your reply, you are not much difference from people who you called bull-shit, maybe their BS is smaller than your BS.  Remove your own position  and look at them as competition of belief construct. 

[gadget73]

For what it's worth, I've never been able to pick up any radiation from a vacuum tube on my Geiger counter.  Mine will pick up beta radiation too, if any was to be had.

Actually, the only radiation you can get from the valves is soft X-RAYs, which are mostly absorbed by the glass anyway.
For that, you need ones that run at high enough voltage.
Which is quite rare these days.
I talk about the effect here, including a video of the glow: http://www.ribbonfarm.com/2015/11/23/artisanal-hand-crafted-electrons

quite so.  The hottest tubes I have in regular use see 660v on the plates.  I could poke around inside of my 1953 TV set and get some readings, but I don't really feel motivated.  HV on that I believe runs around 9kv.   

 I have part of the items needed to set up a gamma spectroscope, but I lack the detector and a pile of lead bricks to make a sample chamber.  One of those should pick up x-ray as well, but it would be a fair bit of time and money invested to make all that go for no good reason.  I'm just not interested enough in nuclear physics to justify the time, money, or bench space to such a thing. The electronics I got for free but I haven't quite  been able to bring myself to gut them for the boxes.

[Fungus]

At least measure the distortion (sorry, "warmth") on the headphone amp or something...

[daqq]

It is the best invention of mankind, when your muscle and neuron is near expiry, which would you choose - religion or Darwinism?

Depends on which religion:

- the ones where I get roasted eternally in Hell (or variation on that theme) for arbitrarily selected transgressions that I have committed - Darwinistic oblivion take me!
- the ones where I reincarnate without any knowledge of my prior self are as far as I'm concerned oblivion either way.

Basically, unless I get a religion that guarantees I get a nice, lovely, enjoyable eternity, I'd prefer oblivion, thank you very much.

I have part of the items needed to set up a gamma spectroscope, but I lack the detector and a pile of lead bricks to make a sample chamber.

The detector is the nastiest bit really - the simplest would be a photomultiplier and a scintillator. You do not need lead bricks nor any shielding if you just accept a worse SNR and/or do long measurements, then substract the background. You should be able to find PMTs and scintillators relatively cheaply on ebay - though they do suck in the lower energy part of the spectrum.

[alper.y]

Hi,

I am the sender of parcel from Turkey, isoUSBRS422 board. Thank you Dave, I am glad to see my package on Mailbag and very happy. I wrote a post about it on my blog. For anyone who interested in my project, I copied my comments directly here:


Dave is kind enough to allocate time for my package in this video, thank you Dave. He did also show all pictures from Turkey in addition to the board. I am really happy. I hope he didn't miss small Turkish tea and coffee packages in the parcel.

I would like to also say something about his comments. Here they are:

Dave @ 13:52 About my gender

Yes, I am a male.

Dave @ 14:00 About top 10 country

I wish, Turkey would be in top 10 list.

Dave @ 15:51 About photos

Nope, sorry, they are from the Internet.

Dave @ 16:00 About the Trojan Horse

AFAIK, this horse from the movie. Also, ancient Troy is in borders of Çanakkale today. Check: https://en.wikipedia.org/wiki/Troy

Dave @ 16:00 About capital of Turkey

Sorry, Ankara is the capital city of Turkey.

Dave @ 16:50 About the bloody tripod

Damn damn!

Dave @ 17:15 - 18:26 About the isoUSBRS422 board

Here is the story: This is also my first "cheap PCB production in China" experience. I decided to use DirtyPCBs. The cheapest option is 5x5 cm protopack by 14$ and the next option is 25$ with the maximum limit 10x10 cm. If you design a 2x6 cm board for example, it costs 25$. So, I had to stay within 5x5 cm limit. This would be my first PCB from there and I didn't know quality of PCB, practical clearance limits etc. (Check: http://alperyazar.blogspot.com.tr/2015/05/en-close-look-at-dirty-boards.html ) I decided not to spend too much money for the first trial. I use RS-422 converters much more than RS-232 converters in my daily jobs so my primary goal was to fit an RS-422 converter. Yes, I agree that it would be nicer if it also had an RS-232 interface but I didn't want to squeeze components too much for the first trial.

I wanted to hide mess of all "fixed" components from user and put all of them at the bottom. "No user-serviceable part at the bottom!". Resistors at the top are for termination and user may want to change them. So they are at the top. However, components at the bottom may stay untouched. This is the reason why I went to effort for double-sided board. Also, it costs same as single-sided board. Actually, it is designed to stay on spacers. 4 spacers are inside the small pink one shown at 14:50. I think Dave would open it after shooting video, who knows, no problem at all.

I misremembered that Dave likes black PCBs. But he hates them especially the glossy ones. Also, I did promote color of the board in my letter. This is big fail for me, palm face. I wanted to try black colored solder mask option, no mat option at all.

Here are my additional notes:

One of my goals was to see the limits of DirtyPCBs. This is why I also included a tiny IC, SN74LVC2T45. The same circuit can be built using less number and easy to solder components. Similarly Turkey figure at the top is primarily here to see the resolution of silk screen layer. Turkey has wavy borders and it is suitable to test the fab house limits too.

Why is there a Turkish flag sticker at the top? Well, to see how it looks like. Some years ago I saw an Arduino board with Italian flag sticker on it and I wanted to see the case for Turkish flag. I also wanted to say that there are many makers in Turkey too.

Why did I send to EEVblog? Well, just for fun. I have been watching EEVblog for a long time and I always appreciated makers who sent their open source designs to Mailbag videos. I wanted to send one too. isoUSBRS422 isn't a commercial product then I don't need any commercial. As I said, just for fun. It is a good memory for me, thanks EEVblog.

[Stonent]

Man I hate to do this, but it seems also Louis is lined up with Dave

...and all of this on Xmas. I mean God become a baby, a man in order for us to see and understand better what does it means. Sadly those reactions are pushing me to write this up.

In my POV there is a beautiful and deep relationship between "fatih" and "reason".
I am an happy Roman Catholic and I love science.

A quick suggestion for everybody (atheist or not), please do deeper in what you think it is the "Truth". There is no better way to live this life. Just use your reason at 100% (for me it is equal to faith at 100%, maybe brain at 100%= Heart at 100%?). I hope for everybody that "God" or "Atheist" is a beautiful starting point not the "job done" one.

A quick suggestion for Christian people: if you can't provide a concrete reason don't shoot out there things like "you need to believe because you need to believe" or "We need to follow God and I all I can give you are smokey unclear reasons". Christ is a Men in flesh not a theory. Stay with your foot on the ground don't become like "Ned Flanders" in the Simpson. And also please stop to try to convert people, first live your faith and the conversion jazz will take care for itself without any extra effort. (To all who wrote those letters to Dave, I hope your intention was growing in your faith and not converting someone on youtube. Please don't take it personal it is just my point of view)

Finally there is (and will be) no objective proof or equation that tell God exists, like there is no objective evidence that girl is the wife (=will love you for the rest of your life) you are looking for. [BTW is a wife reasonable?] Just because love needs to be a free act, I mean between a "YES" or "NO" you say a free "YES" without any theory science bla bla... That's how love is and it is reasonable and so beautiful like this (thanks be to God).

Dave, if you can, please avoid to spoke about your atheist position putting a bad light of the other ones. That's why I give you a yellow card for using the word "Christmyth", but not worriers I already forgive you.

Merry Xams to you all!

PS: Sorry if I step over the line, I promise I will not do it again. Oh well, maybe on Xmas 2016  .

EDIT: Just found Dustin from SmarterEveryday who is thinking like me, that's cool!

I've noticed over the years that atheists tend to like to say little things to get Christians worked up. They don't tend to bother with other religions though.  They like to focus on things like "Well Jesus couldn't have been born in December." or "The holiday called Christmas was based on a pagan holiday that they stole." 

I just want to say "Yeah, and what's your point? Nobody's making that argument."

Yet somehow, I see those same people buying their kids presents on Christmas. I don't see any of them telling their boss that they want to work the last week of December when everyone else is off.

There's sort of a progression from agnostic to atheist. Agnostics tend to be reasonable people and respectful of others beliefs, but a lot of times atheists just come off as jerks.

I have my own reasons for not being an atheist. I've had some life experiences that are good enough evidence for me. And the fact that none of that would ever convince an atheist doesn't bother me.

[zapta]

I'm an atheist too, and I do enjoy Christmas. It is a colorful and happy time of the year, so I take best from it. And I do hate those atheist activists who go around and file lawsuites against the stores and malls that put out the Christmas decorations or say "Merry Christmas".

They typically file it against government entities, separation of church and state and such. Not the way you describe it.

I love Christmas, wouldn't mind having it a few times a year.  Atheism is lousy with holidays.

[c4757p]

Is there any religious person who can make an argument in his favor, that doesn't sound like one of "it's true because I know it and there's nothing you can say to convince me otherwise" and "you're being a bully so shut up"?

I'm not saying god isn't real. I've just never heard an argument for him that wasn't puerile.

[_Andrew_]

For anyone interested in vacuum tubes here is an old 1943 Westinghouse film on the vacuum tubes
https://youtu.be/tBFNbHZDJpc

Also Ron Soyland's videos on the construction of vacuum tubes are worth a visit https://youtu.be/IUPizgcWimw

[c4757p]

The fluorescence of the glass is direct, caused by UV radiation produced in the tube from contaminants and stray gas. I see it on metal halide lamps on start up, where the glass outer quartz glows blue for a few seconds until it is overwhelmed by the light output of the main emission. There it is very visible, as you have 100W of initial UV light being blocked by the glass.

Interesting - in retrospect I should have thought of this effect, but here I was completely stumped as to what caused it.

[Stonent]

The fluorescence of the glass is direct, caused by UV radiation produced in the tube from contaminants and stray gas. I see it on metal halide lamps on start up, where the glass outer quartz glows blue for a few seconds until it is overwhelmed by the light output of the main emission. There it is very visible, as you have 100W of initial UV light being blocked by the glass.

Interesting - in retrospect I should have thought of this effect, but here I was completely stumped as to what caused it.

Most fluorescent lamps are by nature UV producing.  The white coating on the inside absorbs the UV and emits white light.  That's why commercial UV sanitizing lights don't have that coating.