Hi today, i'm gon na make cathodic ray or electron gun, or you know one of those things that's used in old, crt, tube tvs that would shoot electron and draw a picture on the surface of the tv. Well, i'm not gon na make a tv just the electron gun right after i clean this mess, what that's, how engineers work or makers or whatever? If their desk is not like this, it means they are not working. Well. I've never made something like this before, but i might know the science behind it from what i understand.

You connect a very high voltage dc, like 10 kilo, 20 kilo volts or higher to something like this, which is a point connected to negative, called cathode and like a disc, with a hole at the center to positive, called anode. So electrons accumulate over the pointy cathode and this disk becomes positive and if the voltage is high enough, electrons start escaping from the cathode and go to the anode and because there is a hole at the center, they continue going forward, except doesn't quite make sense. Let me see, if i understand see if there is an electron, a little bit off-center to the disk say closer to the top side. There would be more force pulling it towards the top side than the lower side, so it should instead of going straight forward.

It should deflect up like this, in which case you'll just hit the positive anode and goes back to the power supply and for electrons those right at the center. That c equal pull from the disk would go straight and continue going straight. So from my educated guess, every other electron that is a little bit off center would curve and go out like this, and i suppose a whole lot of them will just hit the disc. Is that right? I guess we'll test and see like i said i don't have any experience building one of these and why research, when i can just build and see what happens anyway, i'm gon na use my zvs driver circuit.

I made a while back my sponsor skillshare. An online learning community of professionals gives the first thousand viewers to use my link in the description, a free trial of skillshare premium membership. You can learn from many different subjects for free during this period with no interruptions, after which it's less than just 10 dollars a month on an annual membership, so start learning. Now this circuit creates, like 20 30 kilovolts of high voltage dc.

So i guess i'll just make my anode and cathode and see what happens: eh messes with my lights, here's a washer! I want to use as anode, okay, here's, the anode and cathode. Let's turn it on and see. If i can see any faint trace of electrons jumping between them, i can hear it, but i don't see anything. It might just be the distance between high voltage man.

It gets you when you least expect it. Okay, let's try again i'm gon na change. The gap between the two and see what happens we'll see there is a tiny bit of corona discharge oops. Maybe not that close.

I feel a wind blowing on my hand through that holder, when there is high enough voltage in air because of the concentration of charges in the terminal, the charges jump out and ionize the air molecules around it because of our pointy cattle. There is a huge concentration of electrons at the tip that ionizes a ton of air, and now the negative air is repelled from the negative terminal same as in my van de graaff experiment. Away like this, they flow to the positive terminal, creating wind and they leave their electron on the terminal, which means there is electric current. The wind will continue blowing a bit past anode, let's what's going on, someone is not happy down there.

Let me show you the wind see: oh, it even puts the fire out. The wind is so strong. Wow burn my finger. Okay, i need one of this long type wow.

Why is it shocking me? Oh well, it is high voltage ow. What if i put the flame between them, it starts on arc right away. Hot air is ionized and very low resistance for very high voltage for low voltage. It's like open circuit, well see how far the wind blows through the hole and see if i increase the air gap, there is almost no wind.

If the terminals are further, the attraction is weaker and the current is less the closer. They are. The higher the current high current heats up air that ionizes better and at some points the air totally breaks down, creating a low resistance channel that a glowing hot arc runs through. I just remembered something in a lot of cases.

They make the electrode of the cathode glowing hot, because in that case the atoms of the electrode start vibrating hard and have a lot of energy and the electrons become much more fluid and it's much easier for electrons to escape. Maybe i should do that. Here's how my circuit and transformer is i'm thinking to use a heater element which i'll cut a piece of resistant wire from my hairdryer element and put it there, and i want this to be isolated from the rest of the circuit. So i'm going to run a single turn of wire around my transformer core to get enough voltage to run enough current to heat it up.

Let's try it here. We are, i passed the wire through the core and put a piece of heating element at the end and let's see if it can heat it up at all. Oh, this thing keeps arcing here and they're like there is no tomorrow i'll, just put a piece of electric tape to isolate it, better. Okay, let's try it again.

Well, it works, but i guess i have to pick a longer piece of wire for more resistance to limit the current, so it doesn't melt right away. Okay, here is a longer piece. Oh there you go here. We are folks, let's see if the electrons flow much better.

Now, oh, it's glowing, it does seem like it jumps easier now the experiment needs to be done in a vacuum. So i guess now i have to buy a vacuum. Pump stay tuned, hey! I bought a tiny vacuum pump and i'm gon na use the vacuum chamber. I made a while back for my tesla coil just that the ceiling gasket underneath it is broken.

So i bought one of these silicone sheets that they use for cooking food or something and i'm gon na cut a gasket and put it there just like this. Let's hope it seals my chamber well here. I'm gon na put a balloon in there to see if it expands ready. Apparently there is a exhaust port that you have to open before turning it on.

There is a bit of texture on this silicone too. Maybe that's not helping i'm going to glue this silicone with silicone to the base to make it seal better. There we go. Let's try again.

Well, unfortunately, the vacuum seal is not that great, but doesn't matter. Let's start testing, i place my anode and cathode at a distance of around 9 to 10 centimeters and right now my circuit is on, but there is no way for the high voltage to jump across such a big distance, see in air. The concentration of molecules is so high that electrons jumping out of the cathode stick to them and ionize them. That also creates a tiny glow at the terminal.

Then they slowly move to the positive terminal and the electrons jump out. That also creates a glow there. Let's start a vacuum and look for interesting stuff, we'll see, i see some chrono discharge on the edges of everything. Look at that.

Okay, my power supply immediately jumped to 10 amps. Okay, the vacuum is getting stronger and this is around the maximum vacuum i can get and i have 5 volt 10 amp power supply in vacuum. Electrons have no way but to directly jump across the gap without hitting any air molecules, so they accelerate to huge high speeds, depending on the voltage across the gap, they're almost weightless and there's no one to stop them, and this is what we call cathode ray or Electron beam, electrons don't glow on their own, but because we typically have partial vacuum. The super high speed, electrons, sometimes bang against the remaining air molecules and the exchange of energy, makes the molecules glow.

Now i'm going to increase the energy connecting to a battery that can supply much more current at 12 volts and, let's see, look at this wow. What are those clumps of energy there? Is there some wave going on? Clearly, there is still some good amount of air molecules in there that heat up and rise and create this curve back to the 5 volt supply voltage, i get a much more uniform radiation, although i can't see it in the gap. Maybe i should have replaced the gas with something that would glow now i connected a tiny heating element there. Let's see if that makes a difference, no difference there when there is no vacuum.

Okay here it is with the 5 volt supply. Only okay. Let's turn on the heater, oh, i don't think it made much of a difference. Maybe my voltage is so high that the arc itself creates enough heat and i don't need a heating element.

Like i said, atom vibrations in a very hot metal is so high. Electrons literally fall out of it, and that makes it much easier for electron to shoot out when a negative voltage is supplied. In fact, that's what they use in the old vacuum. Lamp components that, thanks to the heater, could run at a much lower voltage like 200 volts.

A simple diode was like this, because electrons were oozing out of the heater. There would be electric current if the voltage was supplied this way, and not the other way around. This time, let's connect to the battery wow and turn on the heater yeah yeah. It didn't make much of a difference and see when i turn off the heater, it still stays heated because of the arc.

Well, my vacuum chamber is not perfect and maybe my voltage is too high, but now, let's do something drastic. Let's use my marks generator to create hundreds of kilovolts across this thing. Just that, i'm pretty sure at those voltages i would create some pulses of x-ray. So, let's not do it very long here goes, mr marks.

The pulses are very short, but the voltage is super high. That makes the electrons go very fast and tons of instantaneous current illuminate the entire channel. Well, i was hoping to see some electrons passing the hole on the other side. Maybe if i had filled the chamber with a bit of noble gas or had some fluorescent sheet to illuminate them anyway, vacuum tubes are replaced with modern silicon components, thankfully, but i'm sure cathode ray has its application in lab settings or some niche cases.

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