I worked on radar systems since the mid-seventies in Marine aviation. I have had a basic understanding of magnetron operation all these years and even taught electronic theory as an instructor, but this was the clearest, most accurate description of what is truly happening, that I've ever heard. Thanks!
@@JohnNy-ni9np...its adjustable for military purposes. Long range dissipation is very high. A so called horn focuses the beam. A ordinary sheet of aluminum foil can already protect 100% by reflection.
Dont worry - an insulator of the RF output feeder is not made from beryllium oxide ceramic. Nobody, even Chinese, makes domestic equipment with it. This one is made from Al2O3 with a little manganese doping which defines its color. So yep, basically this is a technical ruby ceramic. Also you can do a simple test when in doubt of containing beryllium - just flash a 360-365 nm UV light on it: corundum ceramics will luminescence with deep red ruby-color and beryllium ceramic shows a weak purple luminescence. BTW, if anybody interests, the kitchen oven magnetron is just one of the big family - in other magnetron types, like pulsed for radar, coax-type, relativistic MILO or spatial-harmonics mode, the construction and electric field patterns are much more complex but working principle is close the same.
I was in tactical communications in the Army in the late 80's and early 90's and we used a 5 cavity tunable Klystron as our High Power Amplifier. All the basics are pretty much the same. You do a VERY good job of breaking this down and explaining this function. I really enjoyed this video. Thanks.
I was a US Navy electronics technician in the mid-60's so I feel I have a better-than-average understanding of the science. Your explanation of the principles behind the magetron are, by far, the best I've ever seen. I especially highlight your illustration of capacitive-magnetic resonance. You have done an excellent job!
FINALLY. after about 20 videos, I find a good explanation of the cavity magnetron! Thank you. Whoever took the components & operation of a discrete LC circuit and recreated the effect in a solid lump of copper by just using geometry was a genius.....pure inspiration.
Best description of how a cavity magnetron works I've ever seen. One thing to point out though "This could melt you from the inside out without you even knowing" You *will* feel burns from microwaves in the 2.4Ghz (yeah, microwave ovens use the same frequency as old WiFi) region, they vibrate water molecules so you will definitely notice the burning. Microwaves are used in crowd dispersion devices (higher frequencies, less penetration) because you can feel them and they *hurt.* The high voltage is a hazard, but a microwave isn't going to cause burns much more serious than a 2000 watt IR heater, especially at a distance. A microwave oven exploits the fact that the waves bounce and are close to the magnetron. If you turn it on outside the enclosure you're more likely to damage sensitive electronics as well as draw the wrath of whoever governs RF frequencies where you live than get badly burned.
Yeah I've seen a guy comment on a similar video, he thought the oven stopped working so he put his head inside to check something out and he described the feeling as getting very dizzy, but nothing more serious. And it's the brain we're talking about, so it's definitely not that dangerous. And anyway it takes a while to get some heat to build up, with the brain thing it wouldn't be a surprise if the actual molecular vibration does something weird rather than heat alone.
In addition to the correct statements you and @Techalyzer have already made, microwaves also just don't penetrate that far. When cooking food, anything more than about 1" thick will heat much more slowly. For practical purposes, if you can arrange the food to reduce thickness, including putting an indentation in the middle of malleable solids like rice, mashed potatoes, etc., you can heat the food more evenly and quickly. For humans, this means that yes, some potential for injury exists if one really just ignores the pain involved before things get hot enough, but it's unlikely organs deep in the body would be affected much if at all.
I wonder if is this going on in Ukraine. During the Bosnian war very expensive anti radar site missiles would get to blow up decoys made of ovens rigged to operate with the door open. Probably the highest ratio of cost to kill ratio of any tech warfare kit.
@@echodelta9 Shortwave diathermy machines were used for similar purposes in WWII, though instead of disrupting radar seeking missiles they disrupted a radio beam intersect used by bombers. IIRC it was called the battle of the beams.
The electrons alone won't cause any radiation, even when you spin them by the magnet. What makes the microwave energy is the combination of the electrons moving aronund the cavities, forming a kind of "electron whistle" (the theory is a bit more complicated, but on some aspects the electron movement becomes somewhat similar to what the air does in the regular whistle). The high voltage combined with the magnets is use to make the electrons to move along the cavity tops to form that whistle, without the magnetic field they would just fly straight into the cavities, so no whistle.
Actually they do and the video explained that. Any electron that undergoes acceleration releases photons. He said the magnets were put there to make it "more efficient".
it's about resonannnnnnnnce. RF is all about resonance, really. What frequencies and what proportions -- and especially geometry. The magnets provide a field for the electrons to surf against and curve into a spiral, it's together with the force of the electric field reacting against the uniform magnetic field that creates motion at a right-hand independent vector. The electric waves radiating out of the center would merely be attenuated by reflection by the LC tank of the copper cavity, but realistically I'd wonder if it would just cease to operate from damage overheating after a short time without the needed magnetic field to transform the radiated energy into EM waves with transmission capability.
A warning about that few kV capasitor would be nice, since old ones might not be able to discharge themselfes on their own anymore (built-in resistor could burn out over time), so during disassembly it's always good to check by bridging the leads with some conductor with a good isolated grip/preferably on a stick.
Good general advice for any power supply, really. For really high voltage stuff in the Navy, we had shorting probes and, in extreme cases, thick rubber gloves. I want to say protection up to around 30Kv with both. Which reminds me of an actual maintenance check documented in the technical manual for an air search radar I worked on, that dated back to the 50's or so. It was called the "tinfoil test" and was a way to test the "crowbar" circuit that was supposed to shut down the radar's high voltage in the event of a short. You would take a piece of foil and wrap it around the end of the copper rod of the shorting probe, fanning it out for a couple of inches. Then, you would glove up, open the cabinet to get access to the high voltage connection, connect the probe's ground clip, then bring that fanned out piece of foil, slowly, close to the HV connection. Before you make contact, it'll arc to the foil, burning a hole in it, until the crowbar kicks in and shuts it down. You then measure the size of the hole burnt in the foil. If the hole is too big, the crowbar was too slow, and it fails the test. I got to be first in my class at school to do that test. Makes a rather startling pop, too. 🙂
I used to repair microwave ovens. I've stripped lots of them. The reality is that if you test the capacitor, the voltage is gone in seconds. It's all BS.
To test a magnetron , you measure the voltage at the terminals. If the magnetron is dead, you'll get maybe 2.2KV and if it's good and drawing current it will drop to about 1.9KV. Got to use a high voltage 1000 times probe in the meter to measure
Great video! One mistake I noticed though was in the explanation of LC circuit oscillation. The mistake was the presence of a magnetic field in the inductor when no current was flowing, at 6:59 and other moments, and reasoning that the collapse of the magnetic field at 7:05 is what resets the polarity of the capacitor. Instead, what actually happens is the magnetic field would begin to collapse once the voltage across the capacitor is 0V and the current is maximum, at about 6:54 in your animation. Only THEN would the magnetic field have collapsed, and the inductor would oppositely charge the capacitor to how it is seen at 6:59. I love EM, so I couldn't let this little inaccuracy slide ;) Cheers!
hahahahah thank you. The presence of a "static magnetic field" is actually just a pause in the animation while explaining. In real life it would be fast as you say, the field collapsing after the voltage passes the threshold.
@@ELECTRONOOBS You're welcome! Just wanted to clarify that an inductor's magnetic field will only collapse in this circuit when the voltage across the capacitor is zero.
I believe you got something wrong there, as the magnetic field is proportional to the current in the inductor, so the magnetic field has its maximum amplitude when the capacitor voltage is zero. Thinking if it in another way: Energy must be conserved, so when theres no cahrge in the capacitor (0 V) The energy must all be stored in the magnetic field
I worked in a reprocessing plant for electron RF vac tubes. From a very small 1.5Kw to a huge 357lb (with water jacket) 3.2 Gw vacuum tube and all sorts in between. I learned a lot. How electrons are emitted and controlled by electromagnet oscillation. This video was very informative and not overly technical. Thanks for a job well done.
I have done years of magnetron research but have never until now seen a presentation suitable for an introductory physics or engineering course. Great job!
Thank you! I have seen multiple explanations how a magnetron works in textbooks with drawings, but it makes much more sense for me seeing the inside of it. Also your explanation was better than my 100€ physics textbrick. It finally makes sense.
Very good presentation. I was trained at Varian Assoc. in my earlier years, designing and making both magnetrons and klystrons. It was all about copper, powerful electromagnets, EHT, shf, amps and heat. Our klystrons were used for both radar and TV transmitters and consumed many 100's KW of mean power. The ones I worked on not only emitted microwaves but incidently X-rays which had to checked for safety. The vacuums were typically down to 10^-12 torr if I remember correctly provided by ion pumps. Cant go into too much details (frequencies, output power etc) for obvious reasons but I believe most of this technology has moved over to Solid State!
@@cherylm2C6671 Quite a lot, I studied electromagnetism (Maxwell) and the maths in my own time, linear algebra and basic electrical theory. Our company was also working on the new X-Ray Tomography machines just coming into production. I worked in the section designing and making the cavities, so had to learn to use machine tools as well, to very high tolerances I may add. The smallest klystrons were used by jet aircraft in the nose cones, these were much higher frequencies (X band) but much less powerful.
Thank you for doing this video Andrei. Microwaves are something I've been curious about for some time. I really enjoy the animations you put into your explanations. I'm looking forward to the next video on this topic.
Getting cancer from BeO is near impossible. You have to work at it, literally in a manufacturing job. You can't be hurt by touching or breaking up a BeO bore. It's danger is way overstated. Just don't breath the dust while manufacturing quantities of the bores. (By bore I mean laser bore. I worked in ceramic lasers for 15 years.)
I like this teardown. Subscribed! It needs to be mentioned that the magnetron receives high voltage DC as well as a very low voltage AC from the transformer secondary coils. One secondary coil puts out about 1400VAC, is rectified with a diode and doubled to 2800VDC as it charges and discharges the capacitor in phase. This is connected to the cathode of the magnetron through one of the filament connections. The other secondary coil is a high current 3VAC and is responsible for heating the filament in the magnetron.
Very interesting. You could reuse from 8:00 to 14:00 in a video comparing the magnetron with how a Radar Vacuum tube achieves frequencies and speculate why we do not use tubes in microwaves ( excluding manufacturing as when commercial microwaves started being made, there were vacuum tube manufacturers that could do it ).
Simple reason is cost and efficiency, magnetrons are over 50% effective at generating microwaves, and need no excitation at all, where transmitter tubes need both an exciter stage to drive them, and also filters on the output, plus the typical efficiencies of around 30% is a big drawback, and also the volume they need. Magnetron combines self exciting, and built in filtering cavity filters in it's design, so it is a single part.
What do you mean by "Radar vacuum tube"? Magnetrons _are_ vacuum tubes. Indeed, they are used for certain types of RADAR too. Klystrons aren't altogether too dissimilar in working principle either but they're specifically set up to be able to amplify a signal, whereas a cavity magnetron can only really act as a local oscillator. Handheld RADAR guns use solid state devices (Gunn diodes) and there are now power FET devices that can operate well into the mw band, but when theres no need for a high fidelity, low noise amplifier and all you need is raw RF energy it's pretty tough to beat the humble cavity magnetron.
@@whatelseison8970 The ORIGINAL vacuum tubes used for RADAR had a micro disc inside as the resonator with specific gaps on the inner circumference for the RADAR frequency instead of the size of copper chunk inside a microwave oven. It appears if you increase the size, triple the wattage you can achieve the same frequencies and higher without being in a vacuum.
Thank you for your comment. A radio science newbie is always looking for analog applications. There is still plenty of work for vacuum tube in the industry.
I would like to add since it is not mentioned here, that capacitor inside the microwave WILL kill you if it discharges into you. That is the most dangerous component of the microwave oven and is actually one of the main ways electronics hobbyists die because of their hobby. Always always always make sure that if you take apart a microwave yourself, that you discharge that capacitor, while wearing proper PPE, even if you think it's discharged it is best to verify yourself. Those things can hold a charge for a LONG time. Treat it like a gun. You might think it's safe but it's always best to assume it's loaded.
I smile more with each comment I read that highlights that fact. bleed resistors fail and even so this definitely applies to anything with a power supply, step one... look for the big round things... step two... discharge with appropriate resistor/discharge wand and safety gear! Note some caps can be discharged and then build up a portion of that charge again over a minute or two, so ideally discharge till your sure, make coffee, discharge again and then short with a jumper on bigger caps. I lost a mate to a recently "discharged" cap in a large welder. And the worst part is that ugly process was not instant either... He had a nasty amount of time to reflect and regret.
@@julescircuits845 I know to discharge it but I didn't know it could recover some lost charge. Good to know, not that I'll ever handle a big cap again. But thanks for the education.
@@garymartin9777If a bleed resistor happens to fail that will not show any visible symptoms, the microwave will not fail, you'll basically have no way of knowing. Without a bleed resistor, a capacitor that large could remain charged for many many months. My point is, Always assume the capacitor is charged until you physically verify that it is discharged by attempting to discharge it. Capacitors this large can develop some charge over time if they are not shorted together (through a bleed resistor). Since no capacitor is perfect, some of the electrons go on to store energy chemically, and don't move all the way through the dialectric in the capacitor. This energy isn't released until the voltage on the two poles of the capacitor drops, such as after it has been discharged. A capacitor can "regain" 15% or so of it's max charge this way seconds to minutes after being discharged. (assuming it was just discharged from it's maximum charge). So not only is discharging the capacitor important, but continuing to short both terminals together is important too.
Theoretically microwaves don't come from the hole of the antenna, but really from the insulator, 8:55 those are actually the Heater inputs, anode is grounded on a magnetron, btw nice video
Though video was pretty good, i would like to mention that ''the metal sheath'' you mentioned on the beginning of the video is actually made of mica, and it is interchangeable. If it gets pounced, it can be replaced , and the microwave oven is good as new.
@@cherylm2C6671 I used a plastic film on one of my ovens and it worked for many years with no visible damage. I think that mica is used just as a "worst case scenario", the area doesn't usually get very hot during normal operation.
@@techalyzer I will try that! Thank you for your suggestion! That will make cleaning easier than pushing on that mica plate. break. Fats (or bits of exploded egg) kept away from the magnetron.
This is the best description of a magnetron I've ever seen. Great video! You should do one on a 555 timer if you haven't already. I'd love to watch that.
dude, standing o. Been watching your channel for a while and your visuals and explanation game went exponential recently like 3B1B or Steve Mould or ElectroBOOM level. Keep up the great work.
The safest, for me most useful, component from a scrapped microwave oven is the timer. I kept on forgetting my solder iron, leaving it on overnight until I connected via the timer. I prolly will do an upload to show how it was done. Love these teardowns! Thanks. 🙂
Years ago i took the display/keypad/controller assembly off an old microwave oven and attached a power cord to it and hung it on the wall in the garage. Makes a great wall clock with count down timer and beeper all built in. Great conversation piece.
3:55 it doesn't actually shoot out of that hole like a gun. It radiates around the ring almost like an omnidirectional antenna. thus why waveguides are needed. Great illustration overall fantastic video.
Back in the 70's, at ET "A" school in the Navy, I taught these things. Something like this video would have been nice back then. I made do with drawing a cross section on a chalkboard and trying to describe the electron flow that way. Animation is so much nicer. Our animation was Army films from back when radar was invented, mostly cartoons with sgts yelling and hearing echos. I always found the reflex klystron intriguing, with its re-entrant cavity. The visualization reminded of a popcorn popper, electrons flying up through the cavity, seeing the repeller plate, and reversing back to the cavity. One of the weirder devices, but kind of fun to teach. TWTs, on the other hand. We really only touched on them, and I never worked on them. Taught a brief segment on them, can't say as I really understood them that well, myself. I can say, however, I can remember having to change how we referred to them while I was there. The change happened as we started getting women coming through the school. Before, when we talked about TWTs, they were amplifying tubes. After, we had to refer to them as intensifying tubes. Because we used an acronym to refer to them, and I'll just leave it at that.
@@brolinofvandar Known as Twits in my SatCom days, Did all the theory during my apprenticeship training, now long forgotten. Still makes me shudder working on water cooled klystrons, power off of course, but nevertheless, had to be done.
Amazingly informative video. I learned so much. Also learned I should handle those insulators with more care 😬. Ive taken apart a number of microwaves but never knew what it looked like inside the copper high voltage diode, really interesting way to use induction.
What a great teardown! I've long wondered about the mysterious workings of that magic box in the kitchen. I've always been told not to tear one of those apart for fun. Now I know what to do and not do. You earned the subscription, thanks for that great presentation
Thanks for this video explaining how the cavity magnetron works. I have made a video showing how to troubleshoot simpler microwave ovens similar to yours. I simply explained that the transformer, diode, and capacitor can be tested easily with common meters and tools; and that if you confirm they are all good but there is still no heating, the magnetron can be suspect by process of elimination. My mom still has her 1988 year Sharp microwave. Its original magnetron lasted until 2020. Very well made product! I was able to get a used magnetron from eBay for a few dollars and get it going again without problems. Thanks again for your good explanation!
@@cherylm2C6671 You're welcome. I'll post a link to the video in the next comment. If you only see one comment then it means RUclips is blocking the link.
What a brilliant video! After just replacing a faulty magnetron in my microwave oven I was interested to find out what is inside one and your video explained it perfectly with a great explanation and clear animations. Thanks! I had already pulled the faulty unit apart to salvage the magnets and was aware of not breaking the ceramic insulators, but hadn't gone so far as dremelling the copper anode. I have subscribed. My microwave is an inverter model to vary output power and doesn't seem to have the large capacitor. There are smaller ones on the inverter PCB. It would be interesting to see a video on how inverter microwave ovens work. Thanks again.
Thanks for the video. I didn't know that thorium was used on magnetron cathodes. It will be necessary to disassemble and check the radioactivity in the Wilson chamber or with a radiometer.
Thoriated tungsten is a very common thing, you buy thoriated tungsten TIG welding electrodes cheap, and they go up to 4% thorium, so are well worth putting in the cloud chamber.
No Beryllium in a domestic magnetron, it is way too expensive to use there. Just coloured silica fused to make the insulator/ Still dangerous, but not hazardous.
@@plainedgedsaw1694 Yes, only ever saw beryllia in military and avionics, where you needed the extra performance heat wise, and cost was not a driver. The place where you will find Beryllium alloy though in the house is in things that need fatigue life, like pressure gauges and clock escapement springs, where it is used with copper to make a very fatigue resistant alloy. World production of Beryllium is in the 200 ton per year range, and it is expensive, so no way will that go into a $20 magnetron made by the millions. The ceramic there in a magnetron is purple because they add chromium and cobalt oxides in small amounts to improve thermal shock resistance, and to allow the ceramic to bond well with the nickel and copper alloys used to make the outside envelope and the feed through terminals.
Can you use these parts to create weapons such as portable E.M.P or drone destroyer or others in survival situation. I just need to know im very broke so knowing that i can make wespons and devices would be appreciated.
I worked at a microwave plant in the 90's and would go through the "dud" pallets of magnetrons getting tossed into the scrap dumpster to get all the ceramic magnets out of them. NOW I know how those crazy things work. Thank you!
Let me stick to what I learnt in high school..... Static charges produce electric field, moving charges produce magnetic field, accelerated charges produce electromagnetic radiation. Hence The spiral motion ( an accelerated motion) of electrons between anode and cathode due to the electric field and magnetic field will naturally produce E. M. radiation.
I always wondered how mangnetrons worked. Thank u for creating such a great content so that any newbie could understand how things works. Now I wonder how genius are those who designed this😇
Careful, that is a dangerous circuit. A couple of notes and clarification on the power supply. Note that their are two secondary windings with a common tap. One winding is small and provides a low AC voltage to the filament, something like 5VAC not 2000V. This is only to heat the filament for thermionic emission for your electron cloud. The other secondary winding is about 2000VAC and is tied to the capacitor and diodes to create a voltage doubler that provides a 60HZ pulsing -4000VDC on the filament. The -4000VDC pulsing forces the electron cloud to move out from the filament radially, however, when the moving electrons encounter the magnetic field they curve into an axial flow around the body of the magnetron (remember your right hand rule for electromagnetism).
I took a microwave apart a few years ago. I was playing around with the magnetron lighting up florescent lights and stuff. I unplugged it and discharged the capacitor. Before I made it out of the garage a couple of my friends pulled up. So I showed them what I was messing with. After a lane shoe I unplugged it to take it inside. But this time I forgot to discharge the capacitor. When I picked it up I was fine but when I brought it in to me Ithe capacitor touched my stomach right below my belly button. And 5200v entered my body. I don’t remember anything after that until I woke up in the hospital. My friend told me I picked up the microwave and made a sound like a sprinkler getting air out of the line. Then he said I threw a wild elbow and hit my drill press . Then I took off full speed across the garage. Slammed into the wall, hit the floor. He said I had a look on my face like I was about to kill him. But I was dead. My heart had stopped. He only reason I know this is because my other friend happened to be an EMT. He had my other friend call 911. And he gave me cpr. But he drug me outside and took my shirt off. He knew it would take a bit of time for the ambulance to get to where I lived. I had no heartbeat for 13 minutes. When the ambulance arrived my friend had already been I contact with the other EMTs. so they immediately hit me with the defibrillator. Said the 3rd try my heart started again. But they were worried that I might have brain damage from my blood not pumping properly for that long. If it had only been my one friend I would still be dead. If it had been any one else that night. I would still be dead. Fuct up ending to. About a month later I slept with the sister of the guy who saved me. Which in itself is fuckin weird because we had hated each other for 11 years. But now he won’t talk to me. And his sister even said that she pretty much made me do it. And it is true kinda. I would have never thought it until she made me. Moral to the story is capacitors from a disassembled microwave can kill the shit out of u. So be careful.
You're in the DANGER ZONE! It's funny my 15 year old convection Microwave died two weeks ago and, while I have been waiting for the replacement, I've been deciding what to do with the guts. I think a high current low voltage transformer comes to mind. The Managetron will be disposed of... no point tickling the Dragons tail.
WW2 and the blitz, that one tube at one time was the greatest secret and had to travel to the States and the MIT Rad Lab as one bomb hit and it could have been the setback of the war.
The pink ceramic is aluminum or zirconium oxide doped with chromium to make it pink. I used to scrap these things. They have the neat copper piece in the middle. The best way to get to it is to pry the magnetron apart. Grab them magnets and cut the wires. Then cut the top off where the antenna pinch off is. Next remove the heat sinks off. Finally grind the top and bottom of the resonator at the weld and pop it apart. 🤓
I've always wondered what makes it tick. For me it is mind blowing that some pieces of technology are basically just bent metal and nothing more. You look at the neck of a CRT tube and there's nothing fancy there, just a bunch of metal tubes and strips.
The BIG diode connected from capacitor to chassis has many series connected high voltage diodes inside , so WILL NOT register on most multimeter diode tests ! ...To test , connect via a 1 kΩ resistor to a 24 to 30 Volt DC power source , when forward biased you should read about 10 Volts across a working diode .... FYI , a number of the Ferrite magnets placed on the side of your steel cooker / fridge are a great way to organise your cooking tools ! ... ( tried - n - tested ) ...... DAVE™ ...........
The main example where the standard 0.7v drop flies out the window 🤣🤣 took me a while to figure that out when I first started using em in voltage multipliers....
The 2100 volts capacitor filters de AC current from the transformer. The anode needs at least 2kv to work. This high voltage comes from the transformer working as elevator from 230v. Very good explanation. Thanks.
Ive taken a couple hundred microwaves complete to bare bones, and this is the most informative, scientific, and factual 13 minutes about any machine or device I have ever been witness to. I am well versed so I commend your quality of reverse engineering, photo shooting & editing, public speaking and i have a hunch English is a 2nd language yet you speak better than the people in my neighborhood. Make more. TVs. VCRs. Hard Drives. Vacuums. Water Heaters. Radiators and Air conditioners. You make Bill Nye look softer than melted butter! ;)
With proper safety equipment (gloves, insulated high voltage rated tools), great care and a 5 watt or more bleed resistor across the terminals, around 10-20 ohms should work well.
Fact is, the original Micro Wave ovens cost over $10.000.00 and only a dinner and restaurants could afford one They were expensive due to the cost of making the original "magnatrons". Eventually a much cheaper way of making a magnetron came about and the cost of MWs came way down to the point that MWs can now be had for as little as $50, Yeah I remember the original " Radar Ranges" micro wave ovens.... their name paid homage to its radar genesis
around 13:22 , you said that the microwave transformer generates around 300V AC! i know its just a typo and in the captions it says correctly as 3000V but to just let you know, i pointed this out. Nice video man as always, hats off to you! keep making such informative content🔥🔥🔥
Arthur C. Clarke was a courier during WWII, and he delivered some of the early magnetron prototypes as if they were Regular Mail. By treating them like 'regular post', the deliveries were less likely to draw attention. They were beyond top-secret items at the time; each tube hand-blown as the process to mass-produce was not ready. Clarke had very specific instructions if he were accosted: throw the satchel on the ground roughly, stomp on it firmly, and it there is time, shoot it with your revolver until you run out of ammo. Better to destroy the thing before it is captured by the enemy. Legend has it that he destroyed one tube when he mistook an aggressive beggar for a robbery attempt!
Thanks for all the safety tips and discharging the capacitors are important also, which can be deadly if touched before properly discharged, thanks for all the details, the transformer can be used to make a spot welder for small projects
I've taken many magnetron chambers apart from microwaves for copper scrap, and the silver coating inside applied to the surface of the inner copper magnetron chamber was never explained to me. I've had scrap yard workers tell me the silver coatings are tin but that doesn't explain the multi colors that the silver finish turns when the chamber goes bad and discolors the silvery surface a multitude of gold, orange, red, yellow, blue, purple and greens. I know for a fact silver can acquire these color tones but not tin, and I find it hard to believe they would apply cheap tin to such a delicate operation in these vacuum chambers, so do you know of any manufacturing that can tell us what that silver coating actually is made from?
7:11 Actually, the collapsing magnetic field pushes the electrons in the same direction that created the magnetic field. This pushing charges the capacitor in the opposite polarity to what started the process. Once the magnetic field has collapsed, and the capacitor is now charged (but opposite polarity to what had been imposed), the half-cycle repeats but down in the opposite direction. Analysis: The capacitor pushes current through the inductor but only for so long as the capacitor has a charge. The inductor opposes the increase in current through itself; it does that because a growing magnetic field opposes the applied current. But a shrinking magnetic field pushes it along! So, once the capacitor starts to lose voltage, and the current becomes less, the opposition is also less, and that is why you get a sine wave out of this circuit. At some point the capacitor reaches zero, the magnetic field is maximum, and the magnetic field starts to collapse, generating a current pushing the same direction as before and this charges the capacitor in the opposite polarity.
I worked on radar systems since the mid-seventies in Marine aviation. I have had a basic understanding of magnetron operation all these years and even taught electronic theory as an instructor, but this was the clearest, most accurate description of what is truly happening, that I've ever heard. Thanks!
@@stujones3566 Same - really clear info on the LC circuit.
John, what is the power and frequency used in Marine radars ?
@@Mayosoftware Tesla level stuff man!
@@JohnNy-ni9np sus comment
@@JohnNy-ni9np...its adjustable for military purposes. Long range dissipation is very high. A so called horn focuses the beam. A ordinary sheet of aluminum foil can already protect 100% by reflection.
Dont worry - an insulator of the RF output feeder is not made from beryllium oxide ceramic. Nobody, even Chinese, makes domestic equipment with it. This one is made from Al2O3 with a little manganese doping which defines its color. So yep, basically this is a technical ruby ceramic. Also you can do a simple test when in doubt of containing beryllium - just flash a 360-365 nm UV light on it: corundum ceramics will luminescence with deep red ruby-color and beryllium ceramic shows a weak purple luminescence.
BTW, if anybody interests, the kitchen oven magnetron is just one of the big family - in other magnetron types, like pulsed for radar, coax-type, relativistic MILO or spatial-harmonics mode, the construction and electric field patterns are much more complex but working principle is close the same.
I was in tactical communications in the Army in the late 80's and early 90's and we used a 5 cavity tunable Klystron as our High Power Amplifier. All the basics are pretty much the same. You do a VERY good job of breaking this down and explaining this function. I really enjoyed this video. Thanks.
I was a US Navy electronics technician in the mid-60's so I feel I have a better-than-average understanding of the science. Your explanation of the principles behind the magetron are, by far, the best I've ever seen. I especially highlight your illustration of capacitive-magnetic resonance. You have done an excellent job!
FINALLY. after about 20 videos, I find a good explanation of the cavity magnetron! Thank you. Whoever took the components & operation of a discrete LC circuit and recreated the effect in a solid lump of copper by just using geometry was a genius.....pure inspiration.
the Germans did
I'm not saying this is true, i really don't know, but supposedly, this was alien technology recovered and reverse engineered by americans.
Best description of how a cavity magnetron works I've ever seen.
One thing to point out though "This could melt you from the inside out without you even knowing"
You *will* feel burns from microwaves in the 2.4Ghz (yeah, microwave ovens use the same frequency as old WiFi) region, they vibrate water molecules so you will definitely notice the burning. Microwaves are used in crowd dispersion devices (higher frequencies, less penetration) because you can feel them and they *hurt.*
The high voltage is a hazard, but a microwave isn't going to cause burns much more serious than a 2000 watt IR heater, especially at a distance. A microwave oven exploits the fact that the waves bounce and are close to the magnetron.
If you turn it on outside the enclosure you're more likely to damage sensitive electronics as well as draw the wrath of whoever governs RF frequencies where you live than get badly burned.
Yeah I've seen a guy comment on a similar video, he thought the oven stopped working so he put his head inside to check something out and he described the feeling as getting very dizzy, but nothing more serious. And it's the brain we're talking about, so it's definitely not that dangerous.
And anyway it takes a while to get some heat to build up, with the brain thing it wouldn't be a surprise if the actual molecular vibration does something weird rather than heat alone.
In addition to the correct statements you and @Techalyzer have already made, microwaves also just don't penetrate that far. When cooking food, anything more than about 1" thick will heat much more slowly. For practical purposes, if you can arrange the food to reduce thickness, including putting an indentation in the middle of malleable solids like rice, mashed potatoes, etc., you can heat the food more evenly and quickly.
For humans, this means that yes, some potential for injury exists if one really just ignores the pain involved before things get hot enough, but it's unlikely organs deep in the body would be affected much if at all.
I wonder if is this going on in Ukraine. During the Bosnian war very expensive anti radar site missiles would get to blow up decoys made of ovens rigged to operate with the door open.
Probably the highest ratio of cost to kill ratio of any tech warfare kit.
@@echodelta9 Shortwave diathermy machines were used for similar purposes in WWII, though instead of disrupting radar seeking missiles they disrupted a radio beam intersect used by bombers.
IIRC it was called the battle of the beams.
I read that the microwave bean can get you blind, if pointed directly... I wouldn't try that
Great video!!! You just taught more in 15 min than what I learned and understood out of a college introduction on Microwave Theory in the 80's!
The electrons alone won't cause any radiation, even when you spin them by the magnet. What makes the microwave energy is the combination of the electrons moving aronund the cavities, forming a kind of "electron whistle" (the theory is a bit more complicated, but on some aspects the electron movement becomes somewhat similar to what the air does in the regular whistle). The high voltage combined with the magnets is use to make the electrons to move along the cavity tops to form that whistle, without the magnetic field they would just fly straight into the cavities, so no whistle.
A good explanation.
Actually they do and the video explained that. Any electron that undergoes acceleration releases photons. He said the magnets were put there to make it "more efficient".
Actually I would be very curious to understand that "electron whistle". Would you have any links or explanation ?
it's about resonannnnnnnnce. RF is all about resonance, really. What frequencies and what proportions -- and especially geometry. The magnets provide a field for the electrons to surf against and curve into a spiral, it's together with the force of the electric field reacting against the uniform magnetic field that creates motion at a right-hand independent vector. The electric waves radiating out of the center would merely be attenuated by reflection by the LC tank of the copper cavity, but realistically I'd wonder if it would just cease to operate from damage overheating after a short time without the needed magnetic field to transform the radiated energy into EM waves with transmission capability.
Thanks for the explanation. This is truly incredible every day engineering that we take for granted.
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Newer microwave no longer use brillium oxide so you're perfectly safe but it's the ceramic dust that you should be more caution about
That was kind of an old microwave that's why I tought it could still have... Better avoid it :)
Any dust are dangerous in high volume, maybe he breeze only few micrograms or less anyway everyone will die
@@ELECTRONOOBS I think it’s safe as long as you not breaking the ceramic
Beryllia is very white; a pink tint generally indicates alumina (aluminium oxide) ceramic which is much safer to handle.
@@ELECTRONOOBS it would have to be one of the very, very early microwaves to have BeO (The old Raytheon Radarange for example)
A warning about that few kV capasitor would be nice, since old ones might not be able to discharge themselfes on their own anymore (built-in resistor could burn out over time), so during disassembly it's always good to check by bridging the leads with some conductor with a good isolated grip/preferably on a stick.
Good general advice for any power supply, really.
For really high voltage stuff in the Navy, we had shorting probes and, in extreme cases, thick rubber gloves. I want to say protection up to around 30Kv with both.
Which reminds me of an actual maintenance check documented in the technical manual for an air search radar I worked on, that dated back to the 50's or so. It was called the "tinfoil test" and was a way to test the "crowbar" circuit that was supposed to shut down the radar's high voltage in the event of a short.
You would take a piece of foil and wrap it around the end of the copper rod of the shorting probe, fanning it out for a couple of inches. Then, you would glove up, open the cabinet to get access to the high voltage connection, connect the probe's ground clip, then bring that fanned out piece of foil, slowly, close to the HV connection. Before you make contact, it'll arc to the foil, burning a hole in it, until the crowbar kicks in and shuts it down. You then measure the size of the hole burnt in the foil. If the hole is too big, the crowbar was too slow, and it fails the test.
I got to be first in my class at school to do that test. Makes a rather startling pop, too. 🙂
I used to repair microwave ovens. I've stripped lots of them. The reality is that if you test the capacitor, the voltage is gone in seconds. It's all BS.
To test a magnetron , you measure the voltage at the terminals. If the magnetron is dead, you'll get maybe 2.2KV and if it's good and drawing current it will drop to about 1.9KV. Got to use a high voltage 1000 times probe in the meter to measure
@@brolinofvandar super cool! Thank you for this share
⚡Bang! 💥🤣
I have always wanted to know how magnetrons work and this was incredibly comprehensive. Thank you
Do gigatrons work in similar fashion?
Great video! One mistake I noticed though was in the explanation of LC circuit oscillation. The mistake was the presence of a magnetic field in the inductor when no current was flowing, at 6:59 and other moments, and reasoning that the collapse of the magnetic field at 7:05 is what resets the polarity of the capacitor. Instead, what actually happens is the magnetic field would begin to collapse once the voltage across the capacitor is 0V and the current is maximum, at about 6:54 in your animation. Only THEN would the magnetic field have collapsed, and the inductor would oppositely charge the capacitor to how it is seen at 6:59. I love EM, so I couldn't let this little inaccuracy slide ;) Cheers!
hahahahah thank you. The presence of a "static magnetic field" is actually just a pause in the animation while explaining. In real life it would be fast as you say, the field collapsing after the voltage passes the threshold.
@@ELECTRONOOBS You're welcome! Just wanted to clarify that an inductor's magnetic field will only collapse in this circuit when the voltage across the capacitor is zero.
I believe you got something wrong there, as the magnetic field is proportional to the current in the inductor, so the magnetic field has its maximum amplitude when the capacitor voltage is zero. Thinking if it in another way: Energy must be conserved, so when theres no cahrge in the capacitor (0 V) The energy must all be stored in the magnetic field
The animations that you created to show microwave propagation was perfect at helping me to understand what's happening 'inside the box'.
That's why you want to spin what you're cooking so the waves don't heat up one spot.
I worked in a reprocessing plant for electron RF vac tubes. From a very small 1.5Kw to a huge 357lb (with water jacket) 3.2 Gw vacuum tube and all sorts in between. I learned a lot. How electrons are emitted and controlled by electromagnet oscillation. This video was very informative and not overly technical. Thanks for a job well done.
I have done years of magnetron research but have never until now seen a presentation suitable for an introductory physics or engineering course. Great job!
Hai i need help regarding usage of magnetron for waste management, plz send ur mail id
@@shanthalakshmik6884 Stop lying, there is no use for a magnetron in waste management. Fucking scammer.
Thank you! I have seen multiple explanations how a magnetron works in textbooks with drawings, but it makes much more sense for me seeing the inside of it. Also your explanation was better than my 100€ physics textbrick. It finally makes sense.
Very good presentation.
I was trained at Varian Assoc. in my earlier years, designing and making both magnetrons and klystrons.
It was all about copper, powerful electromagnets, EHT, shf, amps and heat. Our klystrons were used for both radar and TV transmitters and consumed many 100's KW of mean power. The ones I worked on not only emitted microwaves but incidently X-rays which had to checked for safety. The vacuums were typically down to 10^-12 torr if I remember correctly provided by ion pumps.
Cant go into too much details (frequencies, output power etc) for obvious reasons but I believe most of this technology has moved over to Solid State!
Thank you for your comment. What did you have to learn to start doing microwave tech?
@@cherylm2C6671 Quite a lot, I studied electromagnetism (Maxwell) and the maths in my own time, linear algebra and basic electrical theory. Our company was also working on the new X-Ray Tomography machines just coming into production.
I worked in the section designing and making the cavities, so had to learn to use machine tools as well, to very high tolerances I may add. The smallest klystrons were used by jet aircraft in the nose cones, these were much higher frequencies (X band) but much less powerful.
@@tomctutor Thank you for your reply. I look forward to learning more about magnetron applications. Cookbooks now, theory eventually.
Thank you for doing this video Andrei. Microwaves are something I've been curious about for some time. I really enjoy the animations you put into your explanations. I'm looking forward to the next video on this topic.
Nog een nederlander *G E K O L O N I S E E R D*
Getting cancer from BeO is near impossible. You have to work at it, literally in a manufacturing job. You can't be hurt by touching or breaking up a BeO bore. It's danger is way overstated. Just don't breath the dust while manufacturing quantities of the bores.
(By bore I mean laser bore. I worked in ceramic lasers for 15 years.)
I like this teardown. Subscribed!
It needs to be mentioned that the magnetron receives high voltage DC as well as a very low voltage AC from the transformer secondary coils.
One secondary coil puts out about 1400VAC, is rectified with a diode and doubled to 2800VDC as it charges and discharges the capacitor in phase. This is connected to the cathode of the magnetron through one of the filament connections.
The other secondary coil is a high current 3VAC and is responsible for heating the filament in the magnetron.
Very interesting. You could reuse from 8:00 to 14:00 in a video comparing the magnetron with how a Radar Vacuum tube achieves frequencies and speculate why we do not use tubes in microwaves ( excluding manufacturing as when commercial microwaves started being made, there were vacuum tube manufacturers that could do it ).
Simple reason is cost and efficiency, magnetrons are over 50% effective at generating microwaves, and need no excitation at all, where transmitter tubes need both an exciter stage to drive them, and also filters on the output, plus the typical efficiencies of around 30% is a big drawback, and also the volume they need. Magnetron combines self exciting, and built in filtering cavity filters in it's design, so it is a single part.
What do you mean by "Radar vacuum tube"? Magnetrons _are_ vacuum tubes. Indeed, they are used for certain types of RADAR too. Klystrons aren't altogether too dissimilar in working principle either but they're specifically set up to be able to amplify a signal, whereas a cavity magnetron can only really act as a local oscillator. Handheld RADAR guns use solid state devices (Gunn diodes) and there are now power FET devices that can operate well into the mw band, but when theres no need for a high fidelity, low noise amplifier and all you need is raw RF energy it's pretty tough to beat the humble cavity magnetron.
@@whatelseison8970 The ORIGINAL vacuum tubes used for RADAR had a micro disc inside as the resonator with specific gaps on the inner circumference for the RADAR frequency instead of the size of copper chunk inside a microwave oven. It appears if you increase the size, triple the wattage you can achieve the same frequencies and higher without being in a vacuum.
Thank you for your comment. A radio science newbie is always looking for analog applications. There is still plenty of work for vacuum tube in the industry.
That magnetron is a vacuum tube till you cut it open.
I learned about them very long time ago and I was not sure about the concept but now everything is clear thanks man.
I would like to add since it is not mentioned here, that capacitor inside the microwave WILL kill you if it discharges into you. That is the most dangerous component of the microwave oven and is actually one of the main ways electronics hobbyists die because of their hobby. Always always always make sure that if you take apart a microwave yourself, that you discharge that capacitor, while wearing proper PPE, even if you think it's discharged it is best to verify yourself. Those things can hold a charge for a LONG time. Treat it like a gun. You might think it's safe but it's always best to assume it's loaded.
I smile more with each comment I read that highlights that fact. bleed resistors fail and even so this definitely applies to anything with a power supply, step one... look for the big round things... step two... discharge with appropriate resistor/discharge wand and safety gear! Note some caps can be discharged and then build up a portion of that charge again over a minute or two, so ideally discharge till your sure, make coffee, discharge again and then short with a jumper on bigger caps. I lost a mate to a recently "discharged" cap in a large welder. And the worst part is that ugly process was not instant either... He had a nasty amount of time to reflect and regret.
@@julescircuits845 I know to discharge it but I didn't know it could recover some lost charge. Good to know, not that I'll ever handle a big cap again. But thanks for the education.
@@garymartin9777If a bleed resistor happens to fail that will not show any visible symptoms, the microwave will not fail, you'll basically have no way of knowing. Without a bleed resistor, a capacitor that large could remain charged for many many months. My point is, Always assume the capacitor is charged until you physically verify that it is discharged by attempting to discharge it. Capacitors this large can develop some charge over time if they are not shorted together (through a bleed resistor). Since no capacitor is perfect, some of the electrons go on to store energy chemically, and don't move all the way through the dialectric in the capacitor. This energy isn't released until the voltage on the two poles of the capacitor drops, such as after it has been discharged. A capacitor can "regain" 15% or so of it's max charge this way seconds to minutes after being discharged. (assuming it was just discharged from it's maximum charge). So not only is discharging the capacitor important, but continuing to short both terminals together is important too.
Theoretically microwaves don't come from the hole of the antenna, but really from the insulator, 8:55 those are actually the Heater inputs, anode is grounded on a magnetron, btw nice video
Though video was pretty good, i would like to mention that ''the metal sheath'' you mentioned on the beginning of the video is actually made of mica, and it is interchangeable. If it gets pounced, it can be replaced , and the microwave oven is good as new.
Thank you for your comment! Cleaning the interior often is a good insurance. Fat splatter gets hot enough to damage the protective mica.
@@cherylm2C6671 I used a plastic film on one of my ovens and it worked for many years with no visible damage. I think that mica is used just as a "worst case scenario", the area doesn't usually get very hot during normal operation.
@@techalyzer I will try that! Thank you for your suggestion! That will make cleaning easier than pushing on that mica plate. break. Fats (or bits of exploded egg) kept away from the magnetron.
What does ‘pounced’ mean?
@@2Sorts i mean if a hole appears, as shown in the video
This is the best description of a magnetron I've ever seen. Great video! You should do one on a 555 timer if you haven't already. I'd love to watch that.
dude, standing o. Been watching your channel for a while and your visuals and explanation game went exponential recently like 3B1B or Steve Mould or ElectroBOOM level. Keep up the great work.
Your content is so good! Haven't seen all, but I watch most of your clips and often times you inspire me to do more and to try my own projects ❤️
Finally someone explains magnetron in a way that everyone can understand!
The safest, for me most useful, component from a scrapped microwave oven is the timer. I kept on forgetting my solder iron, leaving it on overnight until I connected via the timer. I prolly will do an upload to show how it was done. Love these teardowns! Thanks. 🙂
Going to check it out now :)
Years ago i took the display/keypad/controller assembly off an old microwave oven and attached a power cord to it and hung it on the wall in the garage. Makes a great wall clock with count down timer and beeper all built in. Great conversation piece.
3:55 it doesn't actually shoot out of that hole like a gun. It radiates around the ring almost like an omnidirectional antenna. thus why waveguides are needed. Great illustration overall fantastic video.
Perfectly timed :) please also cover TWT, Relfex klystron and microwave diodes if possible
Back in the 70's, at ET "A" school in the Navy, I taught these things. Something like this video would have been nice back then. I made do with drawing a cross section on a chalkboard and trying to describe the electron flow that way. Animation is so much nicer. Our animation was Army films from back when radar was invented, mostly cartoons with sgts yelling and hearing echos.
I always found the reflex klystron intriguing, with its re-entrant cavity. The visualization reminded of a popcorn popper, electrons flying up through the cavity, seeing the repeller plate, and reversing back to the cavity. One of the weirder devices, but kind of fun to teach.
TWTs, on the other hand. We really only touched on them, and I never worked on them. Taught a brief segment on them, can't say as I really understood them that well, myself. I can say, however, I can remember having to change how we referred to them while I was there. The change happened as we started getting women coming through the school. Before, when we talked about TWTs, they were amplifying tubes. After, we had to refer to them as intensifying tubes. Because we used an acronym to refer to them, and I'll just leave it at that.
@@brolinofvandar Tit for Tat. 😲🤣
@@jlucasound Don't forget the 'W'.... 😀
@@brolinofvandar Known as Twits in my SatCom days, Did all the theory during my apprenticeship training, now long forgotten. Still makes me shudder working on water cooled klystrons, power off of course, but nevertheless, had to be done.
You are genius sir! The video presentations, your descriptions, animations, all of it, learning a ton from you 👍✨ very grateful
You can replace that mica sheet for less than $2 and the oven will work just fine again.
_"and the oven will work just fine again."_ -- well...not _that_ oven. But yeah, in principle it could've been repaired, before it was torn apart. :)
Amazingly informative video. I learned so much. Also learned I should handle those insulators with more care 😬. Ive taken apart a number of microwaves but never knew what it looked like inside the copper high voltage diode, really interesting way to use induction.
While studying radio, I found Inductors and Capacitors are kind of opposites.
What a great teardown!
I've long wondered about the mysterious workings of that magic box in the kitchen.
I've always been told not to tear one of those apart for fun. Now I know what to do and not do.
You earned the subscription, thanks for that great presentation
You long wondered how copper wire and magnets work? The schools suck today?
Wow, this is the best explanation I have ever heard of how a microwave oven and magnetron works.
Thanks for this video explaining how the cavity magnetron works. I have made a video showing how to troubleshoot simpler microwave ovens similar to yours. I simply explained that the transformer, diode, and capacitor can be tested easily with common meters and tools; and that if you confirm they are all good but there is still no heating, the magnetron can be suspect by process of elimination. My mom still has her 1988 year Sharp microwave. Its original magnetron lasted until 2020. Very well made product! I was able to get a used magnetron from eBay for a few dollars and get it going again without problems.
Thanks again for your good explanation!
Thank you for your comment. I'll look for that video.
@@cherylm2C6671
You're welcome. I'll post a link to the video in the next comment. If you only see one comment then it means RUclips is blocking the link.
@@cherylm2C6671
Microwave diagnostic video: ruclips.net/video/v8O3S9H4l_c/видео.html
Wow - this went deep fast. I had no idea that is how they worked. Whoever thought of this was a genius.
What a brilliant video! After just replacing a faulty magnetron in my microwave oven I was interested to find out what is inside one and your video explained it perfectly with a great explanation and clear animations. Thanks! I had already pulled the faulty unit apart to salvage the magnets and was aware of not breaking the ceramic insulators, but hadn't gone so far as dremelling the copper anode. I have subscribed.
My microwave is an inverter model to vary output power and doesn't seem to have the large capacitor. There are smaller ones on the inverter PCB. It would be interesting to see a video on how inverter microwave ovens work. Thanks again.
Just a great video with clear-cut explanations and graphics to show how magnetrons work. Thanks so much!
Thanks for the video. I didn't know that thorium was used on magnetron cathodes. It will be necessary to disassemble and check the radioactivity in the Wilson chamber or with a radiometer.
Thoriated tungsten is a very common thing, you buy thoriated tungsten TIG welding electrodes cheap, and they go up to 4% thorium, so are well worth putting in the cloud chamber.
@@SeanBZA I know about TIG welding.
I have watched thousands of videos on this subject and none and I mean it! none explains it better than you. You are the true king of random🤴
First time I actually understood the process being explained. Well done.
I love the way microwaves heat food , but this blew my mind even more! VERY good video of yours.
seriously! i need to turn on the alerts. i appreciate the level of detail you go into, much more interesting than when it gets glossed over
@@cabasse_music The more you go in detail the more interesting it becomes!
No Beryllium in a domestic magnetron, it is way too expensive to use there. Just coloured silica fused to make the insulator/ Still dangerous, but not hazardous.
Alumina probably.
@@plainedgedsaw1694 Yes, only ever saw beryllia in military and avionics, where you needed the extra performance heat wise, and cost was not a driver. The place where you will find Beryllium alloy though in the house is in things that need fatigue life, like pressure gauges and clock escapement springs, where it is used with copper to make a very fatigue resistant alloy.
World production of Beryllium is in the 200 ton per year range, and it is expensive, so no way will that go into a $20 magnetron made by the millions. The ceramic there in a magnetron is purple because they add chromium and cobalt oxides in small amounts to improve thermal shock resistance, and to allow the ceramic to bond well with the nickel and copper alloys used to make the outside envelope and the feed through terminals.
Can you use these parts to create weapons such as portable E.M.P or drone destroyer or others in survival situation. I just need to know im very broke so knowing that i can make wespons and devices would be appreciated.
I worked at a microwave plant in the 90's and would go through the "dud" pallets of magnetrons getting tossed into the scrap dumpster to get all the ceramic magnets out of them. NOW I know how those crazy things work. Thank you!
You threw out copper like that as scrap?
@Star Gazer It's like 95% aluminum with very little copper but im sure it got separated at the scrap yard by some means.
this video is totally underappreciated
Let me stick to what I learnt in high school..... Static charges produce electric field, moving charges produce magnetic field, accelerated charges produce electromagnetic radiation. Hence The spiral motion ( an accelerated motion) of electrons between anode and cathode due to the electric field and magnetic field will naturally produce E. M. radiation.
I always wondered how mangnetrons worked. Thank u for creating such a great content so that any newbie could understand how things works. Now I wonder how genius are those who designed this😇
Careful, that is a dangerous circuit.
A couple of notes and clarification on the power supply. Note that their are two secondary windings with a common tap. One winding is small and provides a low AC voltage to the filament, something like 5VAC not 2000V. This is only to heat the filament for thermionic emission for your electron cloud. The other secondary winding is about 2000VAC and is tied to the capacitor and diodes to create a voltage doubler that provides a 60HZ pulsing -4000VDC on the filament.
The -4000VDC pulsing forces the electron cloud to move out from the filament radially, however, when the moving electrons encounter the magnetic field they curve into an axial flow around the body of the magnetron (remember your right hand rule for electromagnetism).
I took a microwave apart a few years ago. I was playing around with the magnetron lighting up florescent lights and stuff. I unplugged it and discharged the capacitor. Before I made it out of the garage a couple of my friends pulled up. So I showed them what I was messing with. After a lane shoe I unplugged it to take it inside. But this time I forgot to discharge the capacitor. When I picked it up I was fine but when I brought it in to me Ithe capacitor touched my stomach right below my belly button. And 5200v entered my body. I don’t remember anything after that until I woke up in the hospital. My friend told me I picked up the microwave and made a sound like a sprinkler getting air out of the line. Then he said I threw a wild elbow and hit my drill press . Then I took off full speed across the garage. Slammed into the wall, hit the floor. He said I had a look on my face like I was about to kill him. But I was dead. My heart had stopped. He only reason I know this is because my other friend happened to be an EMT. He had my other friend call 911. And he gave me cpr. But he drug me outside and took my shirt off. He knew it would take a bit of time for the ambulance to get to where I lived. I had no heartbeat for 13 minutes. When the ambulance arrived my friend had already been I contact with the other EMTs. so they immediately hit me with the defibrillator. Said the 3rd try my heart started again. But they were worried that I might have brain damage from my blood not pumping properly for that long. If it had only been my one friend I would still be dead. If it had been any one else that night. I would still be dead. Fuct up ending to. About a month later I slept with the sister of the guy who saved me. Which in itself is fuckin weird because we had hated each other for 11 years. But now he won’t talk to me. And his sister even said that she pretty much made me do it. And it is true kinda. I would have never thought it until she made me. Moral to the story is capacitors from a disassembled microwave can kill the shit out of u. So be careful.
You're in the DANGER ZONE! It's funny my 15 year old convection Microwave died two weeks ago and, while I have been waiting for the replacement, I've been deciding what to do with the guts. I think a high current low voltage transformer comes to mind. The Managetron will be disposed of... no point tickling the Dragons tail.
Be careful!
@@ELECTRONOOBS Always!
Ah, rewinding the secondary to make a spot welder?
0:13 White text over a white background, which is perfect. Congratulations for the enormous amount of editing skills. Wait...
Very nice video! You are the only one explaining it properly...So it's based on an LC oscilator.. Now it makes sense.
The calcination of beryllium oxide at temperatures above 1800°C leads to an almost complete loss of its reactivity.
How did someone dream that up. We're lucky to have these incredible inventions at our disposal just so we can make some popcorn quickly.
As long as it's just the bare popcorn! The other ingredients have interesting properties (and do NOT taste nice).
WW2 and the blitz, that one tube at one time was the greatest secret and had to travel to the States and the MIT Rad Lab as one bomb hit and it could have been the setback of the war.
I know well I've watched other videos before and got lost , this explains it in terms even I can understand!! Brilliantly explained and thanks!
The pink ceramic is aluminum or zirconium oxide doped with chromium to make it pink. I used to scrap these things. They have the neat copper piece in the middle. The best way to get to it is to pry the magnetron apart. Grab them magnets and cut the wires. Then cut the top off where the antenna pinch off is. Next remove the heat sinks off. Finally grind the top and bottom of the resonator at the weld and pop it apart. 🤓
It fulfills my gap of knowledge of microwave theoretically against practically . Thank you very much .
Brilliantly explained and the animated part are very clear. :)
Come on electronoobs deserves more than 500k subs
Absolutely crammed full of information, explained clearly and concisely. 👏
Excellent tutorial on how it works! Thanks! This if by far the best detailed illustrated explanation of how the magnetron works!
Is beryllium oxide more or less dangerous than beryllium Copper.
oh, nice addition to the Utopia soundtrack playlist. What a banger!
Very good tutorial, I was entranced but never bored!
Good video and thank you so much for not having background music or irritating sound effects!!!
one of the best videos actually explaining how a microwave funcitons! great stuff
High frequency circuits are basically magic
I've always wondered what makes it tick. For me it is mind blowing that some pieces of technology are basically just bent metal and nothing more. You look at the neck of a CRT tube and there's nothing fancy there, just a bunch of metal tubes and strips.
I appreciate the way you accurately depict the radiation as perpendicular waves; most depictions are just squiggly lines.
now use the magnetron and make a "brains boiling gun" (BBG)
I can nazi what you talk about
No need man, you just made me BBG of this comment.
@@gottafunk4646 🤣
@@retr0.1337 🤣
*”CIA has entered the chat”*
The BIG diode connected from capacitor to chassis has many series connected high voltage diodes inside , so WILL NOT register on most multimeter diode tests ! ...To test , connect via a 1 kΩ resistor to a 24 to 30 Volt DC power source , when forward biased you should read about 10 Volts across a working diode .... FYI , a number of the Ferrite magnets placed on the side of your steel cooker / fridge are a great way to organise your cooking tools ! ... ( tried - n - tested ) ...... DAVE™ ...........
The main example where the standard 0.7v drop flies out the window 🤣🤣 took me a while to figure that out when I first started using em in voltage multipliers....
Excellent description. Thanks!
I've torn apart 15-20 microwaves for copper salvage and I didn't know that this, knowledge helps avoid slow painful death. ❤
The 2100 volts capacitor filters de AC current from the transformer.
The anode needs at least 2kv to work. This high voltage comes from the transformer working as elevator from 230v.
Very good explanation. Thanks.
Ive taken a couple hundred microwaves complete to bare bones, and this is the most informative, scientific, and factual 13 minutes about any machine or device I have ever been witness to. I am well versed so I commend your quality of reverse engineering, photo shooting & editing, public speaking and i have a hunch English is a 2nd language yet you speak better than the people in my neighborhood. Make more. TVs. VCRs. Hard Drives. Vacuums. Water Heaters. Radiators and Air conditioners. You make Bill Nye look softer than melted butter! ;)
Bill Nye is a hack and a shill for the New World Order. Paid actor.
Cant wait for part 2 .. where you explain more in depth about microwaves .. and how "propagation" happens and why!! 🙏
Great video, but how do you discharge the high voltage capacitor, just wait for a few hours or days?
With proper safety equipment (gloves, insulated high voltage rated tools), great care and a 5 watt or more bleed resistor across the terminals, around 10-20 ohms should work well.
Fact is, the original Micro Wave ovens cost over $10.000.00 and only a dinner and restaurants could afford one They were expensive due to the cost of making the original "magnatrons". Eventually a much cheaper way of making a magnetron came about and the cost of MWs came way down to the point that MWs can now be had for as little as $50,
Yeah I remember the original " Radar Ranges" micro wave ovens.... their name paid homage to its radar genesis
Thank you for helping me thoroughly understand that I don't understand microwaves.
HI 👋 YOU ARE THE BEST TEACHER 👌💓THANKS A LOT...
around 13:22 , you said that the microwave transformer generates around 300V AC! i know its just a typo and in the captions it says correctly as 3000V but to just let you know, i pointed this out. Nice video man as always, hats off to you! keep making such informative content🔥🔥🔥
The correct is 3000V. I've read wrong the script, sorry :)
@@ELECTRONOOBS They are basically an electric chair in a box.
@@ELECTRONOOBS It's 2KV
@@user-lp3cf5yn5b 😂 kill ya volts
Arthur C. Clarke was a courier during WWII, and he delivered some of the early magnetron prototypes as if they were Regular Mail.
By treating them like 'regular post', the deliveries were less likely to draw attention.
They were beyond top-secret items at the time; each tube hand-blown as the process to mass-produce was not ready.
Clarke had very specific instructions if he were accosted: throw the satchel on the ground roughly, stomp on it firmly, and it there is time, shoot it with your revolver until you run out of ammo.
Better to destroy the thing before it is captured by the enemy.
Legend has it that he destroyed one tube when he mistook an aggressive beggar for a robbery attempt!
Thanks for all the safety tips and discharging the capacitors are important also, which can be deadly if touched before properly discharged, thanks for all the details, the transformer can be used to make a spot welder for small projects
"Dr. Who and the Rise of the Magnetrons"? I'D BUY THAT FOR A DOLLAR!
Excellent presentation - thank you. Remember - NO stupid risks, please.
This is such a basic and simple to understand explanation. Thank for this excellent video. May God Bless you. Steven. U.K.
Fascinating stuff. I think your visualisations are top-notch!
Why is this on a Utopia OST playlist?💀
:o Whaaaaaaat? I have no idea. probably the owner of the list clicked "add" without knowing...
@@ELECTRONOOBS yeah probably haha
wdym this is the best song from utopia
I'm glad I'm in the head space that I find this guys videos before i accidentally microwaving myself
Your explenatiion is an art piece. Awesome job.
Awesome demonstration, thanks! I learned about this stuff twenty years ago for radar theory. Perhaps a lesson on cyclotrons next.
I've taken many magnetron chambers apart from microwaves for copper scrap, and the silver coating inside applied to the surface of the inner copper magnetron chamber was never explained to me. I've had scrap yard workers tell me the silver coatings are tin but that doesn't explain the multi colors that the silver finish turns when the chamber goes bad and discolors the silvery surface a multitude of gold, orange, red, yellow, blue, purple and greens. I know for a fact silver can acquire these color tones but not tin, and I find it hard to believe they would apply cheap tin to such a delicate operation in these vacuum chambers, so do you know of any manufacturing that can tell us what that silver coating actually is made from?
7:11 Actually, the collapsing magnetic field pushes the electrons in the same direction that created the magnetic field. This pushing charges the capacitor in the opposite polarity to what started the process. Once the magnetic field has collapsed, and the capacitor is now charged (but opposite polarity to what had been imposed), the half-cycle repeats but down in the opposite direction.
Analysis: The capacitor pushes current through the inductor but only for so long as the capacitor has a charge. The inductor opposes the increase in current through itself; it does that because a growing magnetic field opposes the applied current. But a shrinking magnetic field pushes it along! So, once the capacitor starts to lose voltage, and the current becomes less, the opposition is also less, and that is why you get a sine wave out of this circuit. At some point the capacitor reaches zero, the magnetic field is maximum, and the magnetic field starts to collapse, generating a current pushing the same direction as before and this charges the capacitor in the opposite polarity.
Thanks for the video!
I always wanted this video from you 😇❤️
Awesomely Clear..