MAGNETRON - Teardown + How It Works - Dangerous!

I've just took this thing out of a microwave oven and this is called a magnetron and could be very dangerous I'm especially afraid of this pink part right here these are ceramic insulators but the dangerous part is that they could contain beryllium oxide if you break this ceramic it will turn into dust and if you inhale that dust containing beryllium oxide you will suffocate or get cancer and there is no cure for that so yeah pretty scary thing right anyway the rest of the magnetron are just metal parts and magnets so if you keep them away from high voltage they are safe to examine and yeah these components work with thousands of volts so never connect them outside of the proper shielding of the microwave oven in this video I'll tear down an old microwave we check what component it has inside one by one and then I'll try to explain to you how a magnetron works and what is made of after that we should be ready to understand how the microwave is capable of heating our food using waves that you can't even see it should be a quite interesting and fascinating video so guys let's get started [Music] [Music] PCB way is creating high quality pcbs for prototyping and for very low cost so everyone could use their services so don't hesitate and for only five dollars order your pcbs in just a couple of minutes and improve your projects I've used their services for years and the pcbs are just as I wanted them to be the finished surface is perfect the solder mask as well the size the Vias and the markings are precise you can select all sorts of settings starting from the thickness and the color up to the gold finish for the better conductivity the copper thickness for more current and other specific settings so check pcbway.com for pcbs and other services such as CNC metal engraving 3D printing services and mold injected parts so you could make the entire project at the same time so if you have a good project why not make it perfect using PCB way what's up my friends welcome back this is my old microwave but as you can see inside here this metal part here got a hole in it and because of that it makes all kind of Sparks and doesn't work properly anymore so instead of throwing it away I'll make a tear down and try to explain you the parts that we have and how the magnetron works so once I have the oven open I can take out all the parts we can see a huge high voltage Transformer we also have a huge capacitor on the side and the magnetron which is this part here so I'll take these three parts out in a few minutes I have the Transformer connected to a huge capacitor and the magnetron and we also have an AC fan if you are interested apart from the main components you could also get some buttons maybe some fuses also a light bulb some wires and PCB components another PCB with a Transformer some relays buzzers and other components and you also get another AC motor that is used for the turntable but the components we are interested in are these three here the Transformer capacitor and the magnetron basically these are used to get microwaves which will heat up our food microwaves are a form of electromagnetic radiation with wavelengths rating from above 1 meter to one millimeter corresponding to frequencies between 300 megahertz and 300 gigahertz for a microwave oven those waves will be fit inside of a metal cavity and heat up our food but how is that done is for the next video because today we want to understand how we could get these microwaves out of a cavity magnetron these are the main parts that make such a component we start with the RF output antenna so this is where the microwaves are coming out then we have this pink insulator and this could contain aluminum oxide which is safe but it could also contain beryllium oxide which is very very dangerous if inhaled so under no condition you should break the ceramic insulator and Grate dust from it so stay far from this and by the way if you open the bottom part you can see yet another insulator like this one connect it to the input wires the max return has the mounting plate which is this metal part and we can also see two permanent magnets one on top and one below the tube and then we have the radiator that is used to dissipate the heat because this could get quite hot also to detect when the maximum temperature was reached on the other side we have the thermal switch this component cuts off the current flow when it passes a certain temperature here I have the switch connected to the multimeter and we can hear a beep meaning that the switch is closed I hit it up and after we hear a click the Switch is now open and that's how it works when it gets cold again the current flow opens back okay so on the bottom side of the tube we have a conductive noise suppressor filter coil and the input to the tube and in the middle is the most important part the anode or the resonant cavity you see the magnetron working principle is based on an LC oscillation and we have seen such an oscillation in many other projects basically when we have a capacitor in parallel with a coil we get a so-called LC tank that will resonate at its resonating frequency creating back and forth movement of electrons so here I have a coil in parallel with a capacitor and the oscilloscope is connected as well I apply voltage from my Supply when I remove that voltage we can see some oscillations and this is the resonating frequency based on the coil inductance value and the capacitor capacitance value when we start the capacitor is fully charged and we have no current flow we remove the power supply the charge will start flowing through the coil from one side to the other side attracted by the positive side as we all know this current flow will create a magnetic field around the coil when the current flow is over this magnetic field can't keep any more and it will collapse this collapse will induce a voltage but in the opposite direction and charging up the capacitor with inverse polarity and then when the capacitor is full once again it will create a current flow backwards once again and create another magnetic field so this process repeats over and over creating the so-called LC resonating frequency so basically we'll have a magnetic field rising and collapsing over and over again around the main coil so if I put another coil on the side with an antenna this magnetic field will induce current into the second coil and that antenna will radiate electromagnetic waves this is the basic theory behind the so-called cavity magnetron but this kind of radiation dies out very fast due to losses so to understand the next part we need to open the magnetron but be careful with those ceramic insulators to open the main case we need to bend a few metal parts and the case will just open we'll remove the top metal washer carefully so now we could remove the first magnet then on the bottom side in order to get the tube out we need to cut the filter's wires so cut those wires and then if you pull upwards the tube it will get out now carefully remove the heat dissipator they are just pressed down on top of each other so now we have the main tube made out of copper and believe it or not this could not be used as a high voltage diode right now this is the anode the antenna and the main input terminals so now the tricky part to open the tube carefully using a Dremel tool you cut the copper tube it is quite thick but finally it opened but you will notice the main antenna inside so twist it till you can fully open it and this is what we have inside 10 electrodes all around in the middle we have the filament that is made out of tungsten and thorium so it could withstand high temperatures but also have a good source of electrons so guys how does this work we apply a very high voltage between the filament and the copper anode around it the filament will get very hot and start shooting electrons out with the process that is called thermionic emission just as we have seen in the vacuum tube video but without the copper anode these electrons will stay here but since we have this copper anode all around the electrons due to a voltage difference will accelerate towards the copper anode as the theory of radiation States these charges will produce radiation when they are accelerated and there we have our radiation but this is not efficient at all because the electrons will spend a very short time between the filament and the anode so to make this time longer we add those permanent magnets one below and one above and that will create a magnetic field that will make the electron spin around so now the time from the filament to the anode is a lot longer so the process is more efficient and this is called a hall magnetron to improve the efficiency even more we have the previously seen LC oscillator to achieve that oscillation the anode is designed with cavities as we've seen when we open the magnetron tube as you can see we have 10 cavities made out of the same copper so how could this act as an LC tank because where is the coil and where is the capacitor well for that let's see this example let's assume a copper bar with a cavity when an electron is passing on the side of it it will repel all the others electrons inside of the copper bar right but near the cavity the electrons will have no space above them so they will jump to the other side like that we create a more positive region here and a more negative region here and that's exactly as a capacitor so basically we have 10 capacitors all around and the interesting part is that the curved part of the copper anode will act as an inductor so there we have our LC tank that will resonate so that means that when an electron from the filament is rotating around these cavities it will create positive and negative charge capacitors and these are connected together through the anode wall which will act as an inductor so all these charges will now oscillate at the same time this huge oscillation is now extracted with the antenna which will create a more efficient magnetic radiation this time we can see that antenna here and this was connected to the Copper cavity and this will emit our microwaves and by the way I forgot to mention but the cavities under vacuum so we have no other particles inside even more inside of the cavity since we now have those capacitors with a different polarity the spinning electrons will be attracted by the positive charge regions like this creating a spoke wheel pattern the capacitor charges are oscillating so the spoke wheel will spin like this and that's pretty much what's happening inside of a cavity tube of the magnetron basically the antenna is now radiating the needed microwaves to hit our foot be aware that this can be very dangerous if not kept inside of the metal casing of the microwave oven this could melt you from inside out without you even knowing have in mind that this works with thousands of volts out of this huge Transformer and this usually delivers a little voltage of around 300 volts ac and also around 500 milliamps of current in the future video I want to explain to you how these microwaves are able to hit our food and how the microwave oven Works internally to create the bouncing waves but more about that in the next video I hope that you have learned something new and if so consider giving me a like or comment below thanks again and see you later guys hey guys so we are at the end of this video so some of you guys are supporting me on patreon and thank you very much for that because thanks to you I'm able to buy all these components and the modules that I use for my tutorials and if you would like to support me as well you have the links for my patreon for my website and my shop Below in the description thank you for everything

Channel: Electronoobs

Views: 679,014

Keywords: microwaves, oven, teardown, learn, magnetron, cavity, waves, inside, how it works, radiation, homemade, beryllic, transformer, high voltage, test

Id: 3JNQgdT8LWc

Length: 14min 6sec (846 seconds)

Published: Sun Dec 11 2022