How a Microwave Oven Works

Engineer Rudy Dehn tells us how a magnetron works and how it cooks food in a microwave. Mr. Dehn helped develop both the 915 Mhz and 2.45 Ghz microwave oven at General Electric in the 1960s-80s. He shows us the cathode and anode and describes how microwave energy is created using a filament, magnets and resonating cavities. He takes apart a magnetron and shows us each part and what it does.

[@SerenoOunce]

New rule: How It's Made has to be narrated by actual engineers. Very informative. Thank you.

[@miyesven9405]

listening to how a microwave work from the guy who friggin designed it is hella amazing!

[@ryanmccoy8980]

He didn't design it, he helped design some early models for GE, but he didn't invent it. The guy who invented it was actually an 8th grade dropout. Look it up, no joke.

[@dg-hughes]

More info on EdisonTechCentre website: Albert Hull invented the magnetron which was used for RADAR, Percy Spencer when exposed to microwaves discovered a chocolate bar in his pocket melted that's how he came up with the idea for the Radar Range (microwave oven).

[@jonbryn4]

Lol

[@mscir]

Early life Spencer was born in Howland, Maine. Eighteen months later, Spencer's father died, and his mother soon left him in the care of his aunt and uncle. His uncle then died when Spencer was just seven years old. Spencer subsequently left grammar school to earn money to support himself and his aunt. From the ages of twelve to sixteen, he worked from sunrise to sunset at a spool mill. At the later age, he discovered that a local paper mill was soon to begin using electricity, a concept little known in his rural home region, and he accordingly began learning as much as possible about the phenomenon. Therefore, when he applied to work at the mill, he was one of three people hired to install electricity in the plant, despite never having received any formal training in electrical engineering or even finishing grammar school. At the age of 18, Spencer decided to join the U.S. Navy. He had become interested in wireless communications after learning about the wireless operators aboard the Titanic when it sank. While with the navy, he made himself an expert on radio technology: "I just got hold of a lot of textbooks and taught myself while I was standing watch at night." He also subsequently taught himself trigonometry, calculus, chemistry, physics, and metallurgy, among other subjects.[1][2] en.wikipedia.org/wiki/Percy_Spencer

[@jerrycole2373]

@@mscir That's interesting. Thanks for sharing.

[@ggnutsc]

Reminds me of some of my teachers when I was in tech school. Old guys who knew how things worked and could make analogies and statements to get their point across. One of the best videos I've seen on KZbin lately!!

[@SharonMessage]

Nice, hi Greg.

[@dt6155]

Thank you for sharing these simple but detailed engineering videos with engineer behind the work explaining it.

[@fintimwhimbim]

The man enthuses, I love his nod to the guys that develop the ceramic/metal joint.....a true engineer who loves his field of work. As for microwave ovens, let's not be so harsh in our world where our cigarate smoking, alcohol drinking, sun absorbing, image obsessing habits ruin our kind more so than any technology will ever do.

[@SharonMessage]

Some of us will get hit by a bus in the city of Vancouver LOL

[@C-M-E]

Some of the most intelligent humans to ever walk the earth were also locked to their vices. Tobacco connoisseurs occupy the top notches of that list.

[@fsz9048]

Very helpful to my thesis writing, thank you very much! MR.Rudy Dehn and uploader

[@jimburnsjr.]

Great video, truly inspiring speaker; thank you very much Mr. Dehn, and all who helped.

[@SharonMessage]

Nice

[@mrontheotherside]

Thank you Mr. Rudy Dehn for your time!

[@Katabatic]

Forget all other MW vids. Respect

[@manickamdhayalan]

Great. Thanks a lot Mr Rudy. Just feeling proud of an engineer after 15 yrs of my engineering.!!!

[@Ozzah]

When you blow over the mouth of an empty bottle, you get that resonant sound happening. With the electrons spinning around with these cavities, essentially the same thing is happening as with the bottle, on on an electro-magnetic level. You can make it produce higher frequency waves by making the cavities smaller, or lower frequency waves by making the cavity larger. A cyclotron is very similar to a magnetron, except that it has tunable cavities and costs about 10,000x more.

[@RandomSpongiform]

+Ozzah Not to mention far less practical, though I imagine a cyclotron could technically be used to cook food too. Kinda a waste of taxpayer money though, haha

[@patman0250]

no dude just stop !

[@SharonMessage]

Cool

[@frankservant5754]

Excellent, concise yet accurate description. We need teachers like this

[@TheAmtrack69]

Best explanation yet, on how a magnetron works.

[@Backstabbio]

Fascinating to see this man discuss this.

[@JUSTENization]

I only wished to have .001 of your knowledge, Sir. Thank you.

[@buddysteve5543]

You mean a tenth of a percent (0.10%) of his knowledge, right? LoL!

[@billyraybar]

Should be titled: *Prepare to be humbled in 8 mins by brilliant old man*

[@CBlargh]

Bill Rabara I wouldn't doubt that he's brilliant, but part of what he said was a bit misleading! Microwaves don't cook evenly because the waves are coming from all sides and they don't cook evenly because of fat. They cook evenly because water is a polar molecule and is evenly distributed throughout the food.

[@mohamedhaddaoui1949]

CB BC j

[@shamanahaboolist]

Listening to engineers is awesome.

[@bino46]

so much respect to this old guy

[@OperationAllOut]

Best explanation about magnetron on the entire KZbin

[@SriVarahiSat]

Really I respect him what a great experience.As a Electrical and Electronics Engineer I knew bit but now i am clear about Microwave oven operation May God bless you

[@lawrencejelsma8118]

A very great lecture on the basics of circulating electron generation. This video was like watching Attenborough from those Nature TV shows of those 1970-80s times ... But this time explaining engineering behind a microwave oven. I could listen to his next lecture! 😊

[@chadgaglioti417]

I am amazed how they figure these thing out. So many intricate details working to do one simple thing, heat water molecules. Very cool.

[@Trid3nt861]

such a wise elderly man. intriguing to listen to.

[@Jigaboo123456]

What a good and useful clip/ Not only was Mr.Dehy clever enough to help develop microwave ovens, he is wise enough to explain them simply and without pomposity. I laughed at his " it's less electrically "lossy"-- a great example of keeping it simple and unstuffy, and thus passing on knowledge all the better.

[@240fxst]

thank you for inventing convenience in our daily lives.

[@markwarburton8563]

Great description and graphics. Absolutely right level of detail to get to grips with the basics of arguably one of the more complex pieces of technology that came out of the mid 20th century. Thanks.

[@wwallace4808]

Thank you for posting this informative video. If you have time, describing how the waveguide is tuned to the magnetron would be great. In addition, speaking to the actual field densities seen throughout the microwave cavity would be interesting as well.

[@SharonMessage]

Although I may read english your comment sounded as if it were spoken in another language, respect. God bless

[@patrickbriggs9819]

Always good for a refreshing ideas that we tend to forget over time.

[@GrzegorzDurda]

mind blowing how they visualized the guiding of the electrons and then made it happen. No moving parts.

[@ACogloc]

It's fortunate his invaluable knowledge is saved in the documentation files and patents, and now even his clear explanations are on KZbin for everyone's benefit.

[@ddegn]

It was great to learn this information from Mr. Dehn himself. I learned a lot and and came away with deep respect for Mr. Dehn. Thank you for sharing this video with us.

[@darshansinghjatav7820]

Thank you so much Mr. Rudy.

[@jojojog3789]

Absolutely great video of who it work's has taken me back a few year's of memory to my Technical school and good teachers whom did directly analogue transition of the actual items by breaking down bit by bit and cut away of each industrial mechanical equipment .👌👍

[@ChristopherJones16]

This was something I always wondered growing up. This was very informative for a summary and now I'm hungry for more info on how they work. People today take for granted the use and the invention of the microwave not realizing how amazing and brilliant that box is. Honestly it baffles me how one could even figure out the mere thought and design of a magnetron. That's death ray gun scifi technology then and now. Recently I added another invention/device to the list under microwave and that's how peltiers work. Oh yes. Can't wait to watch that video if it exists. :-)

[@deadprivacy]

+christopher jones the weird thing? it fucking ruins the nutritional value of your food, people taking it for granted is actually damaging their health, amazing invention but to real professional chefs? its a silly fad that wont die but will help you to do so. i for one dont want all the nutritional molecules in my dinner zapped and critically superheated out of existance , however utterly ingenious the design may be.

[@VegasStreetLights]

Methods to cook food did exist before that damn microwave made its way into existence. If it ain't broke do not fix it. Damn scientists try to fix everything that is the real problem

[@A1Skeptic]

+VegasStreetLights That's a strange axe to grind. I'm betting you've got microwaves hitting you right now. Did you know wifi uses the same frequency (2.4 ghz) as a microwave oven? Do you hate wifi too? Hating what they don't understand is a common pastime of fools. Methods of lighting existed before Vegas street lights too. Damn street lights. /s

[@A1Skeptic]

+deadprivacy "i for one dont want all the nutritional molecules in my dinner zapped and critically superheated out of existence..." That's just nutty. Science sure isn't your strong suit. I'm betting you believe a lot of other nutty stuff too. Remember to fear wifi, because it uses the same frequency and is likely zapping your brain right now. /s

[@VegasStreetLights]

A1Skeptic I am not looking to argue. It seems as though you are. You would have lost the argument, because you are misunderstanding what I said. And it seems as though you are misunderstanding what that person whom you replied to said as well. But that is all I have.

[@Centuries_of_Nope]

Such a simple concept that powers a revolutionary machine.

[@playdropfiretopstop]

he is a genius because he actually made it understandable the number one video on this topic should be this guy sadly some kid that sucks at explaining has the top spot

[@KathrynsWorldWildfireTracking]

I have a dream! That one day, people who hate microwaves, will stop watching videos about Microwaves - And cease bitching about them in the comments! March with me!

[@mitch19636]

They have their use still.

[@blameusa7082]

stfu, go be a feminist or something

[@ronaldderooij1774]

@therealnightwriter: Nonsense. Go to bed at night instead of writing. It clears up your mind (hopefully). I am the defender of the Enlightment on a queeste combatting ignorance, nonsense and fairytales. You qualify for all three.

[@nicolaschu9599]

Hey therealnightwriter, do us a favor and pick up a science book. Do you realize how silly you sound? That's not how it works -_-

[@basavaiahbollu6443]

Kathryn Davidson, can't guess what's your problem with microwaves.

[@krasssertyp]

I just took my old microwave apart and really learned something out of this video, thanks for that! One question: I can imagine that the electron emitting kathode wears off over time and consequently, there won't be electrons left to be emitted. What is the service life then for such cathodes? Same question goes for CRT TVs.

[@Electroblud]

John Doe When emitting electrons, the cathode pulls more of them from the powerline, so that's not the problem. However the filament does break after a while du to being eroded by the heat and single atoms getting knocked off the surface. Basically like a good old incandescent light bulb that buns out, thoughslower, because the filament in the magnetron does not get quite as hot.

[@judgeomega]

+John Doe Dont shatter the ceramic around the magnetron. I heard they actually contain highly toxic material called Beryllium whos dust will lodge in your lungs and cause cancer.

[@3beltwesty]

At 6:03 Mr Dehn has a magnetron similar to one in the bottom of my 1971 Hotpoint RHV886 Double Oven with lower "electronic" oven. ie a 915 Mhz Microwave. At 6:17 the actual lower oven of a double oven is seen with the Antenna at the top.

[@Swenser]

Is there a deeper description with math and more practical demo. How did it come to know the sizing of things etc. So many questions, so little time.

[@dg-hughes]

I thought it was odd but I wasn't sure if modern microwave ovens still used vacuum tubes (never had good reason to dismantle one) this answers my question.

[@nadavdanieli]

Very nice comprehensive video.

[@dn7783]

So what you’re saying is the cavity inside the vacuum/how much voltage controls the frequency interesting

[@riccapistrano1131]

Thanks for your contribution to humanity Engr Rudy Dehn. Salamat ng marami, you're a brilliant indeed !

[@realvanman1]

My coffee had gone cool before I found this video, so I popped it into the MW for a few minutes. It was quite enjoyable watching this video, while sipping hot coffee... :) I did not know that early magnetrons operated at only 915 megacycles. I wonder was that the case with the first Amana Radaranges?

[@carmelpule8493]

There is a mistake in how those loops are shown " Instantly rotating in the same direction " at 4:21. If they are current loops then they should be flowing in opposite direction in adjacent cavities and the magnetic loops are rotating, curling, around the radial copper parts again in opposite direction in adjacent radial parts. The E loops and the H loops should be curling each other at any part of the magnetron.

[@grant66800]

Lovely explanation!

[@clems6989]

He us amazing. I could listen to him speak all day.....Thank You !

[@SouthwesternEagle]

I have a 1972 GE microwave. :) Now I know who designed my ancient microwave!!

[@sonofhextall]

Listening to good engineers is awesome.

[@mastopage3120]

Respect to you mister Dehn.

[@haroldoliver]

Electrons boil out of the hot filament. The rest of the set up is to tune the electrons to a frequency which will excite the electrons in the food. It is a ray gun the filament supplies the bullets ...

[@Toqueville2023]

I recently acquired a magnetron and coil from a scraped micro wave. Trying to understand the free energy tech that is happening more and more

[@mscir]

Well done. Why is the speed of rotation of the electrons a function of the voltage?

[@acrobaticcripple8176]

At Last!!! It's now no longer a mystery. What a guy.

[@jefflovenc]

thank you for sharing. nice to see the brilliant old scientist.

[@fidelcatsro6948]

thank you sir rudy! may you live long and healthy life take care god bless you..

[@dylanbrown2782]

arial surfer true

[@dominicnunes2709]

he's dead

[@fidelcatsro6948]

Oh dear when did he leave? Sad december first fidel castro died, then john bedini now this uncle died too?

[@azzym8794]

*I will be the next.*

[@fidelcatsro6948]

God bless you all..don't say such things.

[@robertgift]

WELL DONE! Fascinating! I wish the resonance could be better portrayed. That is the most interesting part. Also gaining (conducting) the power from one of the resonant chambers and radiating it into the oven. How critical are the dimensions fo the resonant cavities? Interesting that he describes the new magnetron as a "tube" - like an old glass vacuum tube.

[@Lianisaa]

This is useful for my task. Thank you for uploading this video😭👏

[@DownhillAllTheWay]

A brave attempt to explain the product of years of leaning microwave theory, in layman's language, and in less than 8 minutes.

[@Altazmuth]

Your doing this presentation is greatly appreciated.

[@rrhone]

Not bad, for an old guy. Very educational and helpful. ty

[@mpadlite2925]

Thanks for this fantastic video!!

[@doright6461]

Where do the electrons ultimately attract to? I am missing the idea of the anode being so close to the "cathode" and the relation of that and the long journey around the oven box. Or why not electrons simply loop thru the magnetron itself?

[@GrantE90]

+Do Right The electrons are only in the vacuum tube. Thermionic emission creates the cloud of electrons around the cathode's filament, the positive anode voltage and magnetic field cause them to oscillate in the tiny copper cavities. Electrons have a negative charge, so are attracted by the positive voltage at the anode (vacuum tubes are like electrostatic particle accelerators: The electric field between the anode and cathode accelerates charged particles like electrons). The probes in the cavities connect to the output stub, which is a quarter wave antenna. From the antenna to the food, it is now photons (radio waves).

[@rui2565]

Thanks, Mr. Dehn!

[@kikikikiki489]

does the antenna output also generate radio frequency or high frequency alternating current?

[@brancarr1]

The man is brilliant. What an invention!

[@Dreamer9317]

The best explanation I have seen on the net, thanks!

[@nshire]

what if you tried to run one from a PAL region in a NTSC region?

[@Retinalism]

You'd get lines in your food?! LOL

[@milliosmiles5160]

+nealshireman Dunno about that, I haven't even managed to get the thing connected yet. Anyone know where I'll find the HDMI socket - I'm starving?

[@CampKohler]

The background image of the photo assemblage at 0:45 is a mirror image as witnessed by the unreadable labels.. Obviously somebody needed the photo be the other way around, so they flipped it photographically to match the foreground image where the "TUBE" label on the anode IS readable.

[@jeylful]

Great speaker, very informative. I quite enjoyed it! Thanks

[@CodfishCatfish]

Excellent, Genius. I knew the fundamentals but this just clarified it all. Brilliantly presented. 10/10 5 Stars.

[@AdiGeorgescu22]

Other than too high of a temperature, what other factors would destroy it in case of overpowering on very short pulses?

[@designertjp-utube]

Truly amazing to see this Brilliant Engineer's Mind still Lucid, Flowing, and Percolating like a Purring Kitten. Rudy Dehn totally understands the *Magnetron* *Energy* *Wave* and was probably approached by The Military way before The Public got a hold of their first Microwave. Attention *PSP* *Millennials* still stuck on reset playing *Minecraft* (while soaking up your *Parent's* *Utility* *Bill* in the same room you grew up in) - _You will not achieve this Engineer's _*_Smart_*_ _*_Level_*_ if you're permanently frozen in your game cubicle, with _*_bouncing_*_ _*_thumbs_*_ , next to a stack of empty _*_7/Eleven_*_ _*_Pizza_*_ Boxes._ S̶o̶r̶r̶y̶ ̶K̶i̶d̶s̶.̶ ̶T̶h̶i̶s̶ ̶v̶i̶d̶e̶o̶ ̶j̶u̶s̶t̶ ̶m̶a̶d̶e̶ ̶m̶e̶ ̶s̶e̶e̶ ̶*T̶h̶e̶* ̶*C̶i̶r̶c̶l̶e̶* ̶*o̶f̶* ̶*L̶i̶f̶e̶* ̶T̶o̶d̶a̶y̶.̶ ̶I̶'̶m̶ ̶a̶ ̶d̶i̶s̶g̶r̶u̶n̶t̶l̶e̶d̶ ̶O̶l̶d̶ ̶M̶a̶n̶ ̶w̶h̶o̶ ̶o̶n̶c̶e̶ ̶w̶a̶s̶ ̶a̶ ̶s̶l̶i̶c̶k̶ ̶'̶7̶0̶'̶s̶ ̶D̶i̶s̶c̶o̶ ̶H̶e̶a̶d̶ ̶w̶h̶o̶ ̶t̶h̶o̶u̶g̶h̶t̶ ̶t̶h̶e̶ ̶S̶e̶n̶i̶o̶r̶ ̶C̶i̶t̶i̶z̶e̶n̶s̶ ̶f̶r̶o̶m̶ ̶t̶h̶e̶ ̶'̶5̶0̶'̶s̶ ̶&̶ ̶'̶6̶0̶'̶s̶ ̶w̶e̶r̶e̶ ̶S̶q̶u̶a̶r̶e̶ ̶O̶l̶d̶ ̶F̶a̶r̶t̶s̶.̶

[@schmittenhammer]

Thanks, great job. So thankful for brilliant scientists and engineers who have made our lives so much easier.

[@hosseinhayati9820]

Can such a magnetron be used to solder hard plast?

[@CampKohler]

The gold ring around the antenna at 4:56 is a woven metal gasket to seal the hole in the waveguide leading to the cooking cavity. Unlike the older round tube, the square tube is almost standardized among all today's manufacturers. The location of the filament terminals, direction of air flow, location of mounting ears, length of antenna (long or short) offer the only variables among almost identical tubes. If you take a magnetron apart, you get great (but fragile) magnets to play with!

[@booshday]

That is a brass mesh washer.

[@rolandsequeira]

Who could have the heart to dislike this?

[@anush7386]

So brilliant and smart man wow

[@mattdathew2794]

great microwave guy

[@cipriansofineti346]

I just want to know what happens if you point it to yourself ,or someone else, your hand or somth, and what is de dangerous distance .

[@DANTHETUBEMAN]

is the anode wave guide a over unity device?

[@maricate]

Thank you Mr. Rudy

[@guitargodthor2]

I never said to try anything out, I said electrons can burn you; if you were either in the microwave or if you stood for a minute directly infront of a stream of them. Otherwise it's completely safe. You are what you eat only implies, if you eat fattening foods, you'll get fat. Where did you hear about medical issues? I'm having trouble finding any articles on such a thing. As far as I am aware, if it caused medical issues, it would have to say so on every microwave sold. It doesn't.

[@AtmaS]

Very interesting and clear presentation. Thank you.

[@Booger6995]

WOW!!! Another one. Got any cite from a credible source to back up that assertion?

[@davidsirmons]

Okay. So, that tiny-ass little wire, in that space, with that voltage, focused like that creates enough power to heat up any organic matter. Change the frequency, multiply the emitter strand by about 3000 times, create an appropriately formed/spaced focuser, and you'll have a microwave emitter that will melt through a battle tank.

[@Blacksheepishot]

What he's essentially saying is, it's an high freq rf generating device which converts dc power+ heat into watts. man I play around with these thing all the time. However, I've never powered em up fully (put a variable transformer on it) without first having proper shielding and most importantly a target...?

[@RajatSolanki007]

great teaching

[@dn7783]

Did you know that water resonates at 2.4 GHz not saying it doesn’t cook things outside of that range but they use that frequency because the microwaves will pacifically target the moisture in the food

[@DuanesMind]

I think it's something to do with the size of the waveguide/cooking chamber is my guess.

[@NHRC569B]

I wish this guy was my grandpa, he's very interesting.

[@computersales]

Stupid question, but I must ask. Some people like to claim the the magnetrons from microwaves are still radioactive when there isn't any power applied to them. I don't believe this, but I don't know for sure either.

[@CJinsoo]

At about 6:00 he comments that the energy waves heat the water or fat content of the food, is this why my oatmeal requires to add X amount of water to the bowl? It’s dried up microwaveable oats in a container.

[@HarryKhan007]

This is the first time I heard anyone talking about the filament.

[@brettmansfield3136]

If the microwaves heat up the water content, what would happen if you microwaved something that was completely dehydrated?

[@imperialdoggo5826]

It would explode.

[@tinkmarshino]

This was very enlightening.. Thanks..

[@neilfrith7864]

god bless these gentlemen we would be up shyt creek if it wasnt for their skill an inteligence.god bless him

[@lwandonteya8352]

He has the coolest Genius hair-do ever.

[@futureskills]

Interesting video