The Electron Gun - the particle accelerator in your house! - F-J's Physics - Video 18
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- เผยแพร่เมื่อ 28 มี.ค. 2018
- Particle accelerator in your house. The Cathode Ray tube and how it works. Old TV and computer monitor screens - why they were not flat screens and why the cases were so big.
Outstanding! This is the first video that I watched from this channel.
Thanks - you are a regular now! I am so pleased you find the videos useful and interesting.
@@AnthonyFrancisJones 😄 This is going to be an exciting journey for me. Through the marvels of physics! And I will be eagerly awaiting your NEET videos. I am a NEET 2022 aspirant and I am sure your videos will help me in achieving a great score in physics.
Thanks for your comments. Hope your NEET went really well!
I had no idea that the old TVs worked this way. I always assumed they just found a way to make the same technology smaller and better. Although this might not be as powerful as CERN's accelerator, it was really educational nonetheless!
Thanks, so pleased you enjoyed it - yes it's a good piece of technology. Younger people might only be used to the world of flat screens now but CRTs are really clever things.
I remember I explained how a CRT works to someone at school. I was very proud and excited I remembered all of it, but the other kids just looked at me a bit bemused 😂 CRTs are really fascinating to me.
You are totally right! They are facinating and you should be proud that you had not only put the effort in to understand them but also explain their inner workings too. They are still facinating but young people may not come across them anymore sadly.
this is to real.
yeah it's unbelievable how so many kids now adays don't even know about CRT monitors, i mean i born 2003, so i'm just 16 now but damn when i talk with people just 3 years younger or something, i feel like a damn dinosaur, they don't know what a "Classic iPod" is or a VHS player or as in this video CRT monitors or anything, while i grew up with these things.
Falconeer, you are completely right, though remember when you were younger you probably did not know much about these things either but you put the effort in, and educated yourself, which is impressive! Some will come to it later on in life and find these devices facinating. You clearly have a much broader knowledge. If you did not know Google 'cathode ray tube memory' or 'The Williams Tube'. This was a facinating use of the CRT as an early form of computer memory. Maybe I should make a film about the humble record player... A neighbour of mine said his kid found a 12" album and thought it was a massive CD! Thanks for the comment and keep up your study of all things technically interesting! And as ever, thank you for taking the time to comment.
@@AnthonyFrancisJones haha yeah i am also in what technically is high school but works kind of like college in sweden, i choose the electrical engineering program because i wanted to build both modern computer hardware and make a living out of it, but also so i can build myself a semi-sophisticated transistor radio (one from like the 50s) as i find old tech extremely facinating. :)
@@falconeer4382 Great - go for it - so many of us started building simple transistor radios and crystal sets (and thermionic valve ones too). It did not matter what they picked up, it was the fact that you could! Get to it before there are only digital stations in the future!
Thanks sir for explaining CRT.
Pleasure Ganesh - glad you found it helped. I might make a film about the electron gun in more detail at some stage too.
it's 4 AM and I really enjoyed the video though I some how knew how it worked
the new part for me was here 4:52 cause I didn't know extra negative potential was needed
I have a large CRT TV set that is sadly not used any more but I Insist on keeping it even if it's video quality surprisingly low compared to modern TVs
Again the video is so great and comfy
Great - thanks for the comment - I spoke to one of my pupils and he just remembered lifting an old CRT TV set and he was astounded by how heavy it was! Glad you can keep yours going. The negative potential is a bit confusing. It is not that it is negative but more that we put a clear potential difference between the cathode/heater/filament and the anode. If you do not connect the negative lead the potential on the filament could be any value depending on the power supply used so it is better to fix it at a known value (actually probably zero in my case) and then we know the anode is 5kV higher. Great observation! Thanks again.
I bet you're a great teacher
Thanks Winston - that's very kind of you. I do love teaching and explaining physics!
Lovely explanation. You are a great teacher, and I'm glad to see your channel is active. I am subbed.
Glad you liked it and thanks for your kind comment - it is a small channel but I hope there is something for everyone interested in physics. Do have a look at some of the other F-J's Physics playlist and see what you think. You might enjoy electron diffraction if you liked this one. Many thanks, Anthony.
Anthony Francis-Jones I certainly will, sir. I do not have the instruments to perform these experiments myself but always wanted to better visualise the stuff we learn about at the classroom. Your channel was a gem of a find.
@@morezco Great - many thanks - makes it all worthwhile. Been rather tied up with the 'Corona Buster' videos recently as schools are closed here and producing them for pupils but I am sure you would enjoy th-cam.com/video/CR2frJzQZ8k/w-d-xo.html Many thanks for your kind comments. Small channel I know but I try to keep the quality high!
I loved this video. As a maintenance tech, we work with something called an Electron beam dryer. It workes at about 500kv, and uses a -30vDC grid, filaments, and vacuum in the 2-6 10^-6 range. I was trying to find more information on a system like that, but I am also very interested to see what that device (in your video) would be used for. What can you do with a stream of electrons, or what could you learn about how matter that passes through it reacts?
Andrew, that is very interesting and a very unusual and specialised system you work on. Sounds like at that voltage there will be issues with X-rays too! Yes, there are so many uses of electron beams. Have a look at my video on electron diffraction for example. As I mentioned the X-ray tube uses an electron beam too. I love the application in this video and think about it being used on the old radar screens too. You might want to look up cathode ray tube memory too. A very early version of computer memory invented in the UK. Thanks for watching and glad you found it interesting and informative.
Can you help me with a doubt? What kind of gas are you using inside the tube, also what is the pressure at which it is filled? I'm trying to make a similar cathode ray tube but my filament burns out within few seconds even after using a vacuum pump to evacuate the tube.
Sounds like a really interesting project. So, I think this tube is fully evacuated and then it has had a small amount of neon added (these Teltron tubes come ready made). There is a set up where you can build your equipment in a large bell jar (we used to have one that sat on top of the vacuum pump) and then evacuate and play with adding small amounts of gas at different pressures. Now, the filament - two things here: you could try taking the filament out of a regular low voltage light bulb as it will be high melting point metal and carefully control the current (however tungsten is not a good electron emitter until it is at very high temperatures) or, what is more common is a heated cathode where it is a coated metal that is heated by a filament that causes electrons to be released from the cathode - not the filament. Good luck but be safe!
@@AnthonyFrancisJones Thank you sir.
Did I miss the part where you applied a vacuum? Does it need one? What do use the beam for? How far and what focus. I have one and an idea but never did it yet. But if you dont need a vacuum i may play it tomorrow. Game changer. I found some real neat uses for a magnetron or three. old stuff has some real powerful stuff in um.
David. this tube comes ready to go for educational demonstrations of electron beams. It is already evacuated (and needs to be for the beam to flow freely) but so you can see the beam there is a small amount of gas in there which ionises and then gives out light. The anode focuses the beam so no external bits needed to do this. They are/were made by Teltron. I think this one is 40 years old. Not done a video with a magnetron - they can be found in microwave ovens for example. Does that help?
@@AnthonyFrancisJones I missed the part o it being a teaching tool. I thought you made it out of a CRT. Sorry bout that. I was all excited to see it work without vacuum because the uses would be staggering. Never worked for me without a vacuum The magnatron is another fun use of an appliance
very good
Thanks - glad you liked it.
What I'm curious about is whether the electrons in the beam attract or repel each other, or if the keep moving along a straight line like a laser beam?
They repel each other due to their charge so the beam lacks focus - it has to be 'pushed' back together using electric fields. Also give some thought to the amount of time the beam traverses the tube and the time the electrons would have to separate due to coulomb repulsion. Thank you for your excellent question. Not dissimilar to 'why is the beam not much lower down on the screen due to gravity?'
@@AnthonyFrancisJones Thank you for you answer!
The reason I asked the question... I know that two wires will attract each other if there are currents flowing in the same direction. But that involves both positive and negative charges. I also know that two equal charges are supposed to repel each other - but again, I've only seen examples of this involving metals (i.e. the wires - a mix of protons and electrons). So I wanted to know whether this "rule" applies in a vacuum too, so that there isn't anything else going on. And the only example of an electron beam in a vacuum I could find was a CRT TV... And that led me here. :)
Do you know of any experiment that proves this, that electrons repel each other in a vacuum? I mean, there can be many reasons why a beam isn't focused. Even lasers tend to get wider with distance, and they don't consist of charged particles at all.
@@alexanderhugestrand good question - the wires is similar but - repulsion and attraction between parallel wires (I need to do a video on this one!) is best thought of as being caused by Magnetic Fields due to the moving charge in the wires - remember it is still negative electrons flowing but their movement in a wire creates magnetic fields around each wire and it is this that causes the forces between them. Remember it is a kind of one wire (turn) electromagnet. You will get magnetic fields in the cathode ray but remember the electrons move so fast that the reach the screen before they have repelled any great distance. The current is also so much weaker. Hope that helps a bit...
Oh, BTW I have done a number of videos of electrons repelling for example in a vacuum away from a negatively charged plate or even the Golf Leaf Electroscope but I agree I have not done one showing the beam widening that would be caused by electron repulsion. I will do a quick calculation later to see how far apart they would repel during the flight time (very short) down the evacuated tube.
Oh and I forgot to say that electrons flowing in parallel wires don't really interact between wires due to their charge as the wires will be neutral anyway - there are atoms' protons in the wire too so you will only get the effect of the magnetic field due to current flow. In a vacuum it is only electrons flowing so they will repel (in all directions) causing the beam to not be as focused as it could be - one of the reasons there is a need for narrow focusing anodes- these can also act as velocity selectors too. Makes for a nice collimated beam. And finally... remember the electrons in a vacuum tube are traveling close to the speed of light but in a wire travel extremely slowly - video on that coming up soon! You have got me thinking!
I'm guessing there's a gas in the tube that allows you to see the light emitted from the electrons? How does that process work for you to see the beams?
I have an old tv in my house sitting doing nothing. Im going to attempt to take it apart for the cathode tube, but what I really want from it is the electron gun for an experiment.
Yes, that's right - in these tubes hydrogen or helium is intentionally put in at manufacture and it is this that makes the beam visible. Be very careful if you play with old TVs at home - I don't recommend it at all unless you really know what you are doing. Firstly the voltages they use are much higher than I am using, and I have to be careful, and they can store dangerous amounts of charge even when turned off and unplugged. You usually cannot see inside the side of the tube as they are coated with a conducting paint and they also have to have a good vacuum so they give a sharp picture. My Teltron tube is especially made for education and demonstration purposes.
It's vacuum inside the tube
@@lancewilson83916 Yes that's right - otherwise the electrons would scatter off the gas and never have enough energy to produce a picture and it would be very out of focus even if it did. You can see the effect of a bit of gas in the tube in this video as you can see the beam. This would of course not be the case in a tv cathode ray tube!
So photons are what we see on the screen?
Yes, that's right - the screen has a coating that when the electrons hit it they deliver their kinetic energy and in the coating (phosphor) this is converted to light. It's how the old cathode ray tube tv produced a picture with different phosphors to give different colours.
nice 1 👍
Glad you enjoyed it.
you are great! :)
Glad you found it useful. Enjoy your physics!
4:10 Ive got a few questions here. I'm assuming the filament being used here is tungsten, like in light bulbs. I'm wondering if molybdenum could be used instead. Molybdenum can't get as hot as tungsten so does that mean it "boils" less electrons thus resulting in a weaker image? I'd love to learn more about this. In addition to this I've seen gun designs that use multiple anodes and a focusing anode. Are these really necessary for rendering a point on a tv? Also, from my understanding in color CRT televisions they use 3 ray guns (R, G, B) and direct these beams with magnetism (deflection system) to fit these rays through a shadow mask (or aperture grille) to prevent the beams from lighting up the incorrect phosphorus dots upon rasterization. How are these three beams angled with such precision?
Brilliant questions all round! So molybdenum has a melting point about 1000 degrees centigrade below that of tungsten so a tungsten filament can get hotter. It can be supported by molybdenum wires to hold it in place as molybdenum has a low expansion coefficient. Most TV electron guns have multiple anodes. Some to attract the electrons off the cathode/filament and others to accelerate the electrons as well as bunch them up and then focus them into a fine beam. This is a fine art and worth reading more about! Read about Wehnelt Cylinders to know more! Yes the arrangement of the guns and the shadow mask are very finely done (mechanically) - that always amazed me as a kid. There can also be corrections included with the tube’s magnetic deflection coils as well. One gun can be used for colour and correctly scanned but three is much better. The shadow mask is very fine indeed. Worth looking up the Trinitron tube as well. Great questions and you have a lot of reading to do to get your head around these interesting designs! Good luck with your studies!
@@AnthonyFrancisJones Thank you for the swift reply -- I greatly appreciate it! I'll be sure to read more about the Wehnelt Cylinder. Also I was reading up on the shadow mask production from a few old patents -- it looks like some manufacturers used a printer for making fine points on some type of transparent sheet and used chemical milling with this printed sheet to etch away the metal to make the mask. I'm left wondering how this printer was made as it seems to be the machine that is making the precise operations. I'm especially curious as to how this was done during a time before ink jet and laser precision. Could a dot matrix printer yield a 0.3mm dot pitch? I'm curious if you know of any other mechanical procedure that is used to make this screen.
Again thanks for the reply. If you know of any books that talk about color CRT television manufacturing or engineering I'd love to know!
@@Drozerix I am not totally familiar with all of the methods used to make shadow masks apart from the photo/chemical-etching one which is similar to how circuit boards are made. It is worth Googling for articles - most of the sales books for CRTs are old and interesting but mainly technical data books such as those produced by Mullard and Ediswan. See what you can find!
Hey man your video was nice I enjoyed
But I have some questions can you please help me out
1.after electron stricking the phosphor screen and after all that glowing where does the electron go from the phosphor screen and if the electrons are not going anywhere then after some time the screen will be too much negative charged and because of that the the flow of electron should stop in some time
Glad you liked it - brilliant question. What you said is true and a problem for these type of tube so there are a number of things that are done. Here are two of the most important. In these tubes the glass is made ever so slightly conducting and so the electrons make their way to ground. In old CRT TVs there is a conducting layer of paint around the tube back - around the bulb shape of glass by the screen - this is connected to a very high positive potential and the electrons therefore flow away to that. There is not a great deal of charge as the beam current is so low but it is still better for picture quality/focus to remove the electrons that hit the screen. Hope that helps and enjoy your physics.
@@AnthonyFrancisJones re: "In old CRT TVs there is a conducting layer of paint around the tube back"
Termed an "aquadag" coating.
Yes, this is a paint that is conducting and contains a lot of carbon.
Hello. Thank you for this video. I have one question - what is the reason of the curved shape? Is it because of a wavelength having the same value for all electrons at one moment, similar to a radius in a circle? I think, using a flat screen would result in only partial coverage or delay at some areas of the screen. Or is it any other reasons behind this shape?
Thanks for the question - not sure I fully understand what you are asking... The beam of electrons is straight as (gravity aside) the only force on the electrons is in the direction of travel. The beam appears as a small dot as it goes through a focusing anode that has a circular hole. The tube is the round shape it is so you can demonstrate bending the beam with magnets in the y and x directions. The electron's wavelength is so small that it really plays no part in this experiment. Does that answer your question?
@@AnthonyFrancisJones The real answer is it does not have to be curved, but curved surface would give you less distortion of the image in a monitor, but it also has to do with vacuum inside, imagine if you had an old fashioned TV tube, of say 25" screen, it would roughly have a screen size of 20" x say 15", this would give you a total surface area of 300 sq inches, and if atmospheric pressure acting on the surface of the glass tube is 15 pounds per square inch, then total pressure acting on that glass screen is 4, 500 Pounds ....that pressure could crush your bones, so these old TV tubes had to be made from very thick glass to withstand these enormous pressures, or else it would implode........ that is one reason why they weighed a ton! So curved surfaces can withstand slightly higher pressure than plain surfaces, as they form an arc as in bridges.
@@mgabrielle2343 Thanks - yes, tube curvature is important for a number of reasons including easier image focusing and structural stability. My tube is spherical at the end for a completely different reason - it has a vertical gun too so can be used to send a beam of electrons into a circular path (a mini CERN in some ways) so you can measure e/m for electrons (I must make that video sometime!). The glass does not need to be very thick (its only a few mm) as it is handled carefully and the pressure difference is never bigger than 1 atmosphere. Making it larger of course does not change the pressure on the outside of the tube either but as you rightly say the total force on the tube's glass grows with area even though the pressure stays constant. So much physics in this simple bit of kit! As an aside old CRTs had glass that varied in thickness depending on which bit of the tube you were looking at. I do at home have some quite large ones that have circular screens - they are really quite old and some tiny round screen ones that have XY plates and came out of CROs. It seems funny picking up a modern oscilloscope as it has not depth to it anymore as there is no CRT!
May you tell what is residual pressure of the gas inside the tube?
I had a look at the original manual for this tube and it mentions Neon at a very low pressure but does not give the value I am afraid. I think it is very close to a complete vacuum but sorry I cannot be more helpful.
If the tube was not filled with hydrogen or helium and was not vacuumed would the regular atmosphere of nitrogen and oxygen still enable ionization of the beam to happen?
Good question. So if there was no gas at all in it - a perfect vacuum you would see no beam until it hit the screen. That's how a normal cathode ray tube is manufactured. A regular atmosphere as we breath would be no good at all - there might be a very short beam and a bit of ionisation but unlikely. The density of the gas molecules would be such that there would be so many collisions of electrons over such a short distance that the beam would not even get as far as the anode. Thus the reason for the vacuum or in the case of this one a very low pressure gas so that students can see the beam. Hope that helps.
Will you be making a level physics videos?
Yes, I will - I have electron diffraction and other ones on my channel but I am trying to do the slightly different types of things from all the stuff that is out there already. Let me know what you think I am missing. I intentionally avoid too much maths as I want people to think, understand, see applications and perhaps things that are not what their teachers always do. Thanks again for watching. Good luck with your studies.
Don't electrons move very very slow though.... Do they move faster in the tube?
Winston, electrons move very slowly in wires - one can consider that there are so many collisions with atoms that they take a great deal of time to move through the wire even though they are individually moving very fast - they end up with a drift velocity. In a vacuum, however, there are no particles in the way so they move unimpeded, close to the speed of light as the 'mean free path' (distance between collisions) is infinite or at least the length of the tube. There is some gas in this tube so they do have some collisions on the way. Great question - you may enjoy this video of mine: th-cam.com/video/BgUnmB27hMk/w-d-xo.html
Perhaps we could convert that kinetic energy into thrust, I had this idea.
Good question - there are such things as ion thrusters but in this case the force is so small as the momentum is so small that you would not be able to get much driving force at all. I will be doing a video on Crookes' Paddlewheel tube at some stage too - though even this is not quite what it seems!
Not at this scale but charged ions are used at a large scale in ion thrusters.
I plan to use this in a mass spectrometer so can it work in less power as well. Like 20V or something
Shivam - interesting - you need a high voltage to accelerate the electrons but in a mass spectrometer you are accelerating ions so it is a bit different. You can use the electron gun to ionise the sample you are studying but typically this is done through strong electric fields which use close contacts and high voltages. So in summary I am not sure how you plan to use it. I need to do a video of a kind of 'mass spectrometer for electrons' where I bend them into a circle and measure e/m, the charge to mass ratio for them. I will still use a fairly high accelerating voltage though.
@@AnthonyFrancisJones I am using it on the moon as part of a mass spectrometer to ionize the elements
I know magnets can harm or damage crts but I don't know if it should be a problem but we have these speakers in front of the tv so I don't know if the speaker magnets would do anything there probably 6-9 inches away from the screen so I don't know if it would effect the picture. The electron gun is further away probably an extra foot away so would the crt get magnetized? I told my dad about it he said it probably would be fine because" there are speakers in the tv" but you seem to know way more then he does.
I am not sure if I know more... but magnets put on an old CRT display can damage it. If you have one that is not important it is quite fun to see the colours change across the screen as the magnetic field affects the display when you put a small magnet on the front of the tube/screen. Gently and this does not do permanent damage but stronger magnetic fields will. The magnetic fields in the speakers may be quite strong but they do not spread out much so should be fine. The speakers in the tv are quite small and these are similar and often have the magnetic field screened from the display tube. So your set up seems fine. Just don't take a strong magnet on its own and pass it over the tube. I am sure someone on TH-cam has done this. I should do a video with my tubes and show the beam being deflected by the magnetic field - this is how some particle accelerators bend the beam into circles. Thanks for a good question.
Anthony Francis-Jones yea that would be cool to see. but because it's a trinitron it has a built in degaussing system and you're welcome.
Can you clear my doubt ?
Doubt - A laboratory has very strong magnetic field upwards, i.e. towards the ceiling. An electron gun is fired towards a wall. The electron will:
Good question - remember the force is always at 90 degrees to the electron movement (current flow) in a magnetic field. And this force is also at 90 degrees to the magnetic field so... the beam will move sideways towards the wall at 90 degrees to the one it is being directed to. Hope that makes sense. It is a version of Fleming' Left Hand Rule (I have a video on that as deflection of electrons in magnetic fields too) Hope that helps.
@@AnthonyFrancisJones Thank you for your explanation........
Can you give me the link of that video?
Sorry - missed your message! Here it is if you still need it. th-cam.com/video/TKPVA1RgUmw/w-d-xo.html
@@AnthonyFrancisJones Its too Late but thanks!!
sir what will happen to the electron after hitting the phosphor screen. is there a return path of electron to complete the circuit?
George, that is a really good question - I cannot remember if I hinted at the answer in this video or another one. So if they stop on the front phosphor of the tube they would build up a negative charge and begin to repel the next electrons coming in so. In the case of a TV this would make the picture less clear. So, firstly the glass envelope (tube) is made slightly conducing to create a return path and in some TVs a positive potential is put on the glass of the tube. You can however often feel the static on the front of a CRT if it has been on for a while - the electrons are earthing through you. Hope that helps and as ever, enjoy your physics!
@@AnthonyFrancisJones Thank you👍✅
I have a question that nobody of my teachers answered. I know that cathode is +ve while anode is -ve but in some cases or diagrams, they both changes their charges. Why does this happen? What are conditions for this reversal? I hope you will answer.
Sufyan, the cathode is where the electrons come from and this should always be made -ve. The anode attracts and accelerates the electrons and therefore should always be +ve. [Are you confusing cathode and anode with cation and anion?]
@@AnthonyFrancisJones Thanks for reply but I a diagram is confusing me. Do you use WhatsApp? so I shall send you the diagram
@@sigma7208 Find me on Facebook and send me a message and I will have a look.
@@sigma7208 send it to afrancisjones@wrekincollge.com
I am assuming that you have received the answer you were looking for by now. However, just in case you didn't, this might help. You have probably seen a connection diagram, or circuit diagram, that showed the anode connected to a ground reference terminal of the power supply,. This works fine because the cathode will then be connected to the negative terminal of the high voltage, or extra high voltage, power supply. As long as the negative and positive terminals of the power supply are floating and not referenced to any other voltage, you can tie either one or the other to ground. It is only required that the cathode be negative with respect to the anode and it really doesn't matter which one is at ground potential. The tubes will work even if neither cathode nor anode are tied to ground but it is common and produces best results, if one or the other is. I connect these Teltron, type D tubes, both ways depending on the tube. For instance, with the Maltese Cross tube, I tie the anode and the cross terminal to a ground terminal on the power supply. That reduces my chances of getting a little zap when I hot-plug the cross, unplugging it and plugging it in again whilst the power is on, to show the effects on the electron shadow due to an electrostatic charge build up on the cross. With regards to the cathode and anode and the accelerating potential difference between them, 0V to +500V is the same as -500V to 0V.
I have a question. How does a 14 year old farm boy reach into the cosmos, and pull this out ? I have heard that at the age of 3 he could draw mechanical operating systems of trains (gee, what took him so long). At 6 he declared he was going to by an inventor. When he was 12 years old he first experienced electricity he could play with, after the family moves. He finds a stash of science related books and magazines. While doing his manual chores he daydreams of the future. He knows that the mechanical system he read about is too slow, and the picture is regulated by the speed of the mechanics. He knows that system will not work. While disc harrowing a field his mind ventures into the ether of the cosmos. He comes back to as mere humans, looks at the rows in the potato field, and there is electronic television.
So it literally only took him a couple months to process information that he read about, and find a solution. He barely has any education at this point, and only a couple of years of college by the end. He was only exposed to electricity, and "ideas of the world" for less than 24 months. So after the 24 months of exposure he changes the human experience, for all humans forever.
The Pal Blue Dot, Hubble images, Mars Rover, Moon landings, satellites images, wars, the way we communicate, the way we learn, the way we entertain ourselves depends on the ability to send images electronically.
This all makes me wonder...... As a child, sounds strange because 14 is a child. OK, as a much younger child if he had access to such questions - ideas, and a family with resources, would he had the idea at half that age? The move to Rigby was what changed the calculation, the exposure of science magazines, electricity on the farm. Would the blueprint for the image dissector been drawn up by an 7 year old? Working prototype by age 9 ? The stories at 3 that he was starting to understand mechanical operating systems by just seeing a train where does that even start? Even counting in utero he's only 4 years old.
The mental capacity has always been there. When exposed to an engineering marvel such as a train he starts working it out. All he had was raw absolute processing power. That was his only advantage. He just had the ability to squeeze more knowledge out of the smallest bits of information. I find it exciting, and to be honest kinda terrifying that someone like that walked this planet.
It is a remarkable story - the young mind unfettered with all the clutter of daily life is very powerful. One is reminded of Einstein looking at the town clock... Remember with many of these 'inventions' they were 'thought' experiments well before they could be turned into reality - a case of 'what if we could do such and such in the future?' I have to remind myself constantly (at my age!) that many great minds did their best work when they were very young from Mozart to Einstein and many others. So there I lay out the challenge to all young minds to do great and useful things!
@@AnthonyFrancisJones I have an idea for you for content and your channel
@@jamessmith-pb8ly Great!
@@AnthonyFrancisJones. I was looking at your content, and this seems like this would be up your alley
I wrote to you about Philo Farnsworth before. It is hard to process what he did, his massive struggles in his life, and the conditions of the world that TV created. He was unhappy with Televison. It is extremely difficult to understand how a kid with 8 years of elementary school education, rural schools at that, changed humanity forever.
How does a kid read a couple of magazines while surronded by dirt fields become the world's leading expert in theoretical physicists specilaizing in the field of experimental electronics? It only took him a few months from not knowing anything other than farming to surpass every public lab, private lab, university lab, every corporation, all the military researchers, every scientist that ever thought about the next breakthrough in communication, observation, and transmission devices.
He told his wife Pem that "I'm going to change the world". Somehow at 19 he was able to convince hard nose bankers to invest and 2 years later have a working prototype. The 1936 Olympics used his and RCA systems, which most of RCA was "borrowed" Farnsworth tech.
Hitler tried to collect him his family said when Hitler was gathering scientists. Philo didn't win his patent war with RCA fully until 1939. RCA was ordered to pay Farnsworth 1 million dollars. That was during the depression. No one took on Sarnoff CEO of RCA. He was one of the most ruthless, rule bending corporate leaders in the world.
I know Philo refused to work on the bomb, but helped with radar, guidance systems, air traffic control, night vision etc. etc. I have never heard of him being arrogant. I have heard he would get highly frustrated when he was working with the physicists at ITT labs while trying to make fusion work. They had a lot more education, but never had the breakthroughs, and he very little education, and groundbreaking achievements.
Philo's sisters said he couldn't turn off his mind, and his processing of information ran full throttle until he would collapse from exhaustion. The older he got the more his body couldn't take it. He becamed addicted to pills, and alcohol. He had mental breakdowns, was given shock therapy.
He did have a great victory with the Moon landing. That is when he told his wife it was all worth it.
The way Philo saw TV was for education, sports, music, but not mindless programming. What you, and others like you are doing with your content is how he wanted TV to go. It may be because he was born in a log cabin, and a rural life. He wanted information for everyone. NASA used a miniature version of his first image dissector tv camera to broadcast from the Moon. I'm sure that had to be the top achievement for him. Humanity gets to see man walk on the Moon because of my dreams.
My point is there is a lot of material, the bad could be sidestepped. There are people left that knew Philo still alive. Robert L Hirsch that worked with him on his fusor is 86. I heard he was still doing good as far as his health. I think there are a few still alive from Brigham Young University which is where he worked last.
There are a few people that you could interview, do a couple of podcasts. Ask for questions from the public before hand. It's in your field on interest. These people that got to be in the room with that kind of talent don't have a lot longer left because of their age.
Scientific American said when Philo died he was of one the top 10 mathematicians of his time. There was some massive talent during his life, Einstein, John von Neumann, the Shockley transistor team, Edward Teller. Farnsworth just wore so many hats in so many fields, and he was the top guy, or one of the top guys, more of a one stop shop.
The more I researched the more it became obvious what a burden he had because he could see some many aspects. Any nugget of information like plowing a field could lead to a working electronic television, or a fusion reactor.
Give it some thought. Hirsch would be number one I would say. You could talk shop, and the direction of the fusion projects around the world. It touches many aspects, climate issues, space travel, going to Mars. a Moon Colony will need some form of nuclear power. I think if you cross promote it with all the interests you could have a very successfull podcast
@@jamessmith-pb8ly Sorry for the slow reply - snowed under with online teaching at the moment! That is a great idea and I am really interested in what you say and your great enthusiasm and knowledge. I will give it some thought. Not quite my area but still something that is worth a try. Would work best with a trip to the USA to film it and some background. What a pain about lockdown and travel restrictions at the moment. Thank you very much - it is great to hear from you.
Kindly give a lecture on deflection of electrons
Amad, that is a really good idea. Thanks for the suggestion. I have two different electron beam tubes that I can demo it in. One with a screen inside it (a bit like an oscilloscope diffraction) and the tube in this video that I can bend the beam into a full circle. It might take a few months but I will have to do that. Thanks again for your great suggestion.
I'm pretty sure these were vacuumed. No gasses. Electrons reacted with the screen panel on the front. The risks of implosions etc are due to the rapid change in pressure
Thanks Cameron. Yes you do see the green on the screen due to the electrons losing kinetic energy and converting it to light in the phosphor but in the bits I did in the dark you will see the whole length of the electron beam so these Teltron tubes had gas (at a low pressure) in them so in an educational situation students could see the beam. Of course in a TV tube there was a hard vacuum and a getter strip to make sure it remained that way. Hope you enjoyed the video.
Is the electron gun vacuum?
The electron gun is part of this whole system - the bit with the anode and cathode that accelerates the electrons. So the do not lose kinetic energy in the tube, the tube itself is evacuated otherwise they would not reach the screen. So all electron guns are normally put in a vacuum. Mine has a tiny bit of gas in it so you can see the beam across the tube but normally one would not want that for example in a particle accelerator (CERN) or an old cathode ray tube of a TV. Hope that helps.
Why do crts wear out
Good question. Lots of things can go wrong. The tube can slowly have air leak in. The heater in the cathode can fail/burn out. Low work function coatings on the filament can come unstuck and reduce the effectiveness of heated cathodes. The phosphor on the front of the screen can, if too much electron energy hits it for prolonged periods of time, get damaged and burn an image into the front of the screen - that's where the idea of screensavers comes in - causes the image to move and not have the beam in one place all of the time. They are in many ways simple devices but these are some of the issues with them over time. BTW don't forget that the power supplies that make them work degenerate over time and it can be here that issues are if they fail to work as well. Hope that goes someway to answering your question and thanks for taking the time to watch the video.
Anthony Francis-Jones I'm going to get one soon but it's sitting in an uninsulated garage where temperatures very from kind of hot to cool and would that effect the picture or not. Also it has been sitting for awhile. But I saw this video where some guy plays a game on a 1953 Muntz tv and it was fine so do I really have to worry about my crt tv.
@@smashingrandomthingzandrev2134 you are at the whim mainly of the power supplies and the state of the cabling internally as well as other components such as capacitors - I cannot see why the CRT itself would not be ok. Remember that if this is a tv the line scan can be different - 405 lines on old ones so you will be having a bit of a play and seeing what happens. I wish you luck.
Anthony Francis-Jones. The tv survived the garage It's just I had to make my dad help me get it in the house but it was worth it so I can play my n64. Now when I turned it on and started using it I noticed slight flickering. Is there a way I can adjust anything to fix it in the future? It's not a problem yet I don't really notice it unless I'm close to it is there a way just in case I ever have to do anything?
@@smashingrandomthingzandrev2134 - There are all sorts of reasons why they flicker but the main one is 'they just do' as they are having to refresh the picture much more slowly than modern systems. So the picture is never as stable as modern systems. It was always noticeable close up or when you take a photo of the screen working - you will see just how slowly the picture is redrawn a line at a time. Shows you what we used to put up with!
I love crts and crooks tubes🤣 what a nerd lol
Nothing wrong with that! My dad (a doctor) talked to me about Crookes tubes when I was a small boy and I guess the interest stuck. His father was one of the first people to have a portable x-ray set. My dad paid the price with cracked nail beds almost certainly from over exposure before the risks were known. I really want to demonstrate the Maltese Cross experiment but I do not have one here. I might have to make one but if I find one I will definitely make a film of it.
Where can I buy this Electron Gun?
Ours is very old but you can try - www.3bscientific.co.uk/teltron-tubes,pg_675.html
I have seen them on eBay too.