Why does your Microwave waste half its Power?

[@ScienceAsylum]

*Clarification:* By saying half the energy is wasted, I only meant that it was available but unused. In other words, the device doesn't take full advantage of what the wall is providing. It only uses 40-50% of the provided potential. I never meant to imply that the energy was dissipated as heat or dumped somewhere else. "Wasted" and "efficiency" felt like good words for that, but apparently I was wrong given the response in the comments. There's some ambiguity there that I did not anticipate. Oops! In hindsight, I can see how this could be misleading. *Minor Correction:* Apparently, modern phone chargers are made with SMPS transformers rather than magnetic transformers. I learned about them in the early days of mobile phones when they were all magnetic transformers. I had no idea they changed the design. This doesn't really affect the video, but thanks for the correction anyway. It gives me another rabbit hole to go down.

[@maxxiang8746]

I think phone chargers usually don't use piezoelectric transformers, but just high frequency ferrite transformers optimized for flyback converters.

[@BlackyBrownDestruction9337]

Thanks for the warning, I was planning on fixing mine but decided to buy a new one

[@misterlau5246]

🧐 That's better, PhD Lucid 🤓🖖

[@ScienceAsylum]

@@maxxiang8746 Thanks. I've edited that word out of the comment until I do more research into phone chargers.

[@jeffpkamp]

I have a class 2 12vdc power supply. It's about 10-30x heavier than my switched mode 12vdc power supply and only able to source half the current (1a vs 2-5a).

[@ElectroBOOM]

Hey awesome, the scope survived!! oh and good, you survived too! 😁 great video!

[@mukundyadav6913]

Someone: Avengers endgame is the greatest crossover of all time Mehdi: Hold my full bride rectifier Nick: Hold my 2,999,792,458 clones

[@omsingharjit]

Mehdi - why not microwave uses efficient smps Stepup ?

[@KeysightLabs]

I guess I'm shipping you another probe lol

[@samuraisystemsllc]

Definitely need you to weigh in on the title, oh great master of the full bridge rectifier. We really don't think it's accurate to say it "wastes half it's power". Please respond Senpai. 😉

[@SeanBZA]

@@omsingharjit Because that is a lot more expensive, so you only find this on the high end microwaves made by Sharp and Matsushita, who make them that way. The transformer, capacitor and diode are cost wise a third the cost of the microwave, and the magnetron is half, the rest being the steel case and everything else. You only have inverter microwaves at the top end of the market, never at the $40 Walmart special end. For inverter you start at $230 from what I see online, and go up in price then.

[@alexrvolt662]

Unless I misunderstood something, the half-wave rectifier doesn't actually waste half of the energy (in the sense : dissipating it to heat) ; it just doesn't let power go through 50% of the time, but during the "blocked" half-period, no energy is taken from the source.

[@axelBr1]

That's what I was thinking.

[@eskiltroll]

I agree with you. It’s not wasted (turned into heat or something), it’s just not used.

[@martin09091989]

Thank u, so i don´t have to tipe so much! ✌

[@samuraisystemsllc]

That was my assumption, as well. There will be losses from the transformer from eddy currents, and maybe it even saturates a bit, but it's nowhere near "Half its power".

[@zygintasmiknius9729]

so whole why your microwave waste half its power thing is incorrect? :D

[@nemurerumaboroshi]

Judging from the amount of damage in the small scale version of the experiment, not trying to mess around with the real thing was extremely wise decision 😂

[@ScienceAsylum]

Agreed.

[@zrglow4450]

One can't be too cautious when dealing with powers surpassing human body durability.

[@pepcorampouch4787]

sure bruddah, dont touch that shit, the inside of a microwawe kills more hobby electricians than ANYTHING related to electronics on this planet, it will fry ur nervous system and brain so bad that youll be dead dead before you hit the ground, its srsly not funny...

[@N0Xa880iUL]

The collab we didn't know we wanted, but the one we deserved.

[@hancarv4705]

Are you kidding? it as has been my wet dream for ages

[@northgrave]

My first thought when Nick started talking about rectifiers was that Mehdi should be consulted. Little did I know!

[@ScienceAsylum]

@@northgrave Apparently, I thought the same thing when I was researching this 😉

[@NoActuallyGo-KCUF-Yourself]

It makes so much sense in retrospect.

[@N0Xa880iUL]

@@NoActuallyGo-KCUF-Yourself Absolutely

[@jeffpkamp]

Half wave rectifiers don't "waste" half the energy, they just don't use it, so it stays in the system. Makes a big difference as dissipating half the energy would be a nightmare depending on how much power you are drawing with the half wave rectifiers.

[@gordonspond]

Exactly.

[@chrisjacobsen1659]

This was almost word for word, what I was gonna post. ^^^ that exactly "waste" is very very much the wrong word.

[@ScienceAsylum]

I've pinned a comment clarifying.

[@gregorymalchuk272]

It introduces harmonic distortion and low power factor to the power grid.

[@csehszlovakze]

@@ScienceAsylum do we have any ballpark numbers on how much energy is wasted *as heat* in this setup?

[@bskull3232]

You are mixing duty cycle (conduction angle) with efficiency. With a half wave rectifier you still can get almost 100% efficiency, you just waste half of your conduction angle, so half of the time your rectifier is not pulling electricity from the wall.

[@alexrvolt662]

yeah that's my thought too. At most you could say it wastes half of the power in the sense : the time-averaged power is half what it would be without the rectifier (so the device must be sized to allow 2000 W, where you have 1000 W "effective" only). But saying that it wastes half of the energy is misleading, bc no energy from the source is lost.

[@ScienceAsylum]

I clarify in the pinned comment.

[@geppettocollodi8945]

A half wave rectifier DOES NOT waste 1/2 the energy, even when configured as voltage doubler. If it did the 1000W oven will put 1000W into the food and 1000W into the kitchen cabinet starting a fire.

[@ScienceAsylum]

I've pinned a comment clarifying.

[@KeysightLabs]

Imagine being me, waking up to find @ElectroBOOM putting my probes in a microwave

[@ScienceAsylum]

😂

[@HAWXLEADER]

Gotta say, I think your products are great! We use them at the company i work at and they're very professionally made!

[@KeysightLabs]

@@HAWXLEADER thanks!

[@alexanderquilty5705]

Just a small arm and a leg for hobbyists at home 😅🥲

[@thomasdavis4253]

Having a working relationship with Mehdi, you should know it is only a matter of time before he puts anything in a microwave...

[@uwezimmermann5427]

The half-wave rectifier is not wasting power or energy. It is just not utilizing the other half-wave. No current is drawn during the other half-wave thus no momentary power is taken from the wall outlet, thus also the integral over all negative half-waves and thus the energy consumed is zero. The only losses are in the finite forward voltage drop over the diode when it is conducting, the tiny leakage current in reverse direction and the fact that the load does not behave like an ohmic load and thus generates harmonics in the electricity grid.

[@pwnmeisterage]

A typical microwave oven taps some AC power for the lamp, fan, and turntable before it goes through the HV transformer. Not to mention any AC power which is tapped off for other power transformers (to power magnetron and triode filaments, the timer and control panel, etc). So in practice much more than half of the available AC power is utilized.

[@uwezimmermann5427]

@@pwnmeisterage in most cases those are insignificant in comparison. And in my statement I was only referring to the half-way rectifier not the total consumption of the microwave oven.

[@arthurmee]

Love the way Mehdi called it a megatron . . 😀

[@rayoflight62]

A 900 Watt microwave oven don't waste other 900 Watt as heat. The half wave rectifier simply doesn't present a load to the secondary winding of the HV transformer, when the diode is reverse biased. This load unbalance cause the magnetic field in the transformer core to be skewed toward one polarity. In theory it could saturate the iron core, but the core is designed to operate that way. The current peaks charging the paper-in-oil capacitor are present only at half wave, 60 times per second in the US. In contrast, a full wave rectifier would work on both half waves, showing a 120 Hz ripple. But the oven is built to be as cheap as possible, by saving either three diodes, or a tap in the secondary winding. The transformer has another low voltage winding to light up the filament of the magnetron, which is also the cathode from where the electron are emitted and spun into the multiple LC circuit (in a vacuum). These tuned circuits are made of wavy copper. Of the multiple LC resonant cells inside a magnetron, the antenna output can be connected to any of them; the geometry operating the electrons beam rotation under the influence of a static magnet (at a fixed frequency, equal to the resonance of the water molecules) is a kind of black magic. Keep in mind that a magnetron is one of the very few application where a vacuum tube (the magnetron itself) hasn't been replaced with a semiconductor equivalent. Thank you for the great video!

[@ScienceAsylum]

I clarify in the pinned comment.

[@1234j]

Congratulations on 600k! Your uploads are BRILLIANT! Cheers from England.

[@ScienceAsylum]

Thanks! I'm still shocked 600k people want to follow my work.

[@bytefu]

@@ScienceAsylum Oh come on, you've got some brilliant episodes, you put so much effort into them and explain things much better than most KZbin scientists do. In fact, you should have much more subscribers, given how good your videos are.

[@AlleyKatt]

Enjoyed seeing a "trained professional" who knows "how to work with electricity without..." so easily fry a diode and bake a capacitor. Another fun and educational lesson in your library. Loved it.

[@ScienceAsylum]

😆 Sure, but I didn't get hurt!

[@paulmichaelfreedman8334]

I often play with breadboards and home made designs, and I cannot count the times I've blown up Electrolytic caps by putting them in wrong way round. Always that little pop, and then "Uhhhh!" (me)

[@jskratnyarlathotep8411]

@@paulmichaelfreedman8334 tantalum caps do the same, but much more violently, btw

[@Lucky10279]

@@paulmichaelfreedman8334 Why not just use unpolarized capacitors so you don't have to worry about it?

[@iamjimgroth]

@@paulmichaelfreedman8334 I actually haven't had it happen one single time. That's not because I'm awesome. Rather I'm kind of crap, but I've been lucky as a leprechaun for many years now.

[@artdonovandesign]

Great to see you again, Nick ☺ Mehdi's guest spot was hysterical AND informative- as always. Three Cheers for Science Asylum and ElectroBOOM!

[@raven4k998]

imagine how powerful a microwave would be if it's transformer was 90%instead of 45% efficient🤔

[@universeisundernoobligatio3283]

As a kid 9 year old started playing with electricity by blowing up capacitors for 9 transistor radios with my RC car power supply. Uncle got me the radio on my birthday, only lasted a month before I took it apart. 58 years later I'm a retired electronics engineer, life long electronic hobbyist still fascinated by electronics still blow up stuff.

[@ScienceAsylum]

Sounds like electronics really had an impact on you 🙂

[@marquisdemoo1792]

In the early 1980's, whilst working on a faulty device designed to detect trigger signals for remote control bombs in an Ops Room in Northern Ireland, I mistakenly assumed the circuit was rated for 12V when in fact it was 6V so on connecting a 12V battery the electrolytic capacitor exploded filling the Ops Room with little bits of foil. It did not make me popular.

[@johndooley8837]

My age and story is very similar to yours. I seemed to have had some genetic electrical knowledge at a young age. My dad was an electrician (as was his father) and I would use things he had around to wire up batteries, lights and switches that actually worked without ever being shown how to do it. Later when I was about 12 I was given a volt ohm meter and the book Radio Amateur's Handbook, what a book, read it cover to cover many times. Using the books information about power supplies, circuit schematics, dipole antennas, TV frequency charts, coil winding data and using parts from old scraped equipment and vacuum tube TV sets, built a 750vdc power supply and basic oscillator transmitter that could screw up every TV for miles around. Anyway have to go, there are a couple of things on the bench that I want to take a look at..

[@laughing5559]

Great username!!

[@laughing5559]

Took electronics in high school. The lab needed some new bench power supplies but couldn't afford the full price so the school bought kits which had to be assembled by the students. Everyone gathered around the power up of the first completed kit. The cover had not been put on yet. When the switch was flipped there was an explosion and the air in the room became filled with something that looked like feathers. You guessed it! The large primary filter capacitor (electrolytic) had been installed backwards (polarity reversed). That was a lesson I never forgot.

[@kylethompson1379]

I've always found the cavity magnetron to be the most elegant piece of engineering ever made. So many concepts and scientific fields involved in its inception, but ultimately a hunk of shaped metal that is easy to mass produce. It really is genius, the poetry of science.

[@raven4k998]

hey it works it has always worked that's all that matter's

[@baomao7243]

A SUPER clever concept using an electron beam and stamped metal to form the right geometry for the desired RF frequency. The lost art of tubes.

[@agentstona]

I SUBSCRIBED TO YOU IN THE FIRST 9 SECONDS because of the energy you bring i know for sure this will be interesting video channel.

[@greatPretender79]

I like this a lot, nice to take a break from things like gravity and entropy (which can hurt my brain) once in a while!

[@ScienceAsylum]

Agreed. I always need a break and I had fun with this one.

[@artdonovandesign]

I'm still trying to wrap my head around entropy and information and the Landauer Limit!

[@satibel]

At least gravity keeps you grounded.

[@michaelcherokee8906]

Goes to show the rich diversity between us all. I can grasp gravity and entropy just fine, to me it's completely intuitive. Involve electronics or algebra and I check out.

[@Life_42]

So awesome having ElectroBOOM!!! He was recently on The Slow Mo Guys!

[@crimsondragon2677]

“You don’t need it to be perfect. You just need it to work.” Engineering in a nutshell.

[@lajya01]

and programming.

[@crimsondragon2677]

@@lajya01 Coincidentally, I learned both from the same teacher.

[@ScienceCommunicator2001]

But I want it to be perfect, and work

[@otakuribo]

This actually explained some key concepts from electroBOOM videos for me, like the rectifier ⚡💡 Thanks guys!!💙

[@ScienceAsylum]

Happy to help! 🤓

[@MichaelB-wm5cg]

A half-wave rectifier doesn't waste half the energy from the cycle, it just doesn't use it.

[@ScienceAsylum]

I clarify in the pinned comment.

[@rafflesmaos]

I had my OTR microwave suddenly stop working a few months back, and it took a bit to find the fault. First I thought it was the door switches, but replacing those did nothing. Then I decided to check the capacitor, which rightfully scared me as I already knew how dangerous it could have been. So after unplugging, I did a very similar method to what you employed with the pliers and piece of wood, hehe. Turned out the capacitor was completely bad and shorted. Found an OEM replacement for like $15 (just had to search for matching parameters), and the microwave came right back up and running.

[@ScienceAsylum]

I'm glad you survived 👍. The microwave at an old job failed once. Turned out to be a couple burned out thermal sensors. Easy fix.

[@rafflesmaos]

@@gags730 Thanks for the tips! I actually have a few good multimeters already from having to work on other electronics stuff, including an LCR meter for the trickier things. You're right, I should have checked the diode, hopefully it's still good and will continue to be good until I move to a different place and get a new microwave regardless :) This is the second time I had an issue with this microwave too, but at least between the first and the second there was a span of 7ish years of no issues. The first issue was it breaking literally a year and two months after purchasing (aka just out of warranty). That one took a while to figure out, but thankfully the manufacturer included a full schematic. Before finding the schematic, I checked every thermal fuse and saw no problems. Looking at the schematic, I realized that there was one more thermal fuse buried way off on the other side of the microwave. Disassembled the microwave further to get to the fuse, and saw that it just melted and broke the wire due to a bad crimp. Had to get a new temperature and voltage rated wire, new connector, new thermal fuse just in case, crimper, etc... still way cheaper than getting a new microwave or hiring someone else to fix it :D

[@rafflesmaos]

@@gags730 Yep to both questions, including convection cooking. For that year before the connection failed I had been sensing a slightly burnt plastic smell... that was apparently the connector slowly melting under high load until it finally failed. Why, have you seen this type of failure before as well?

[@SeanBZA]

The magnetron is in itself also a diode, and a load. The regular diode conducts on the positive half cycle, charging up the capacitor, then, on the negative half cycle, the magnetron diode starts to conduct, with the forward voltage being the 5kV, as power is being generated in the spiralling electron flow inside the magnetron, charging the capacitor to zero, then to -2.5kV at the peak, with the magnetron then seeing briefly the full 5kV. Thus the 2 magnets in the magnetron, there to make the electrons spiral between the hot cathode, and the grounded cold anode. The spiralling electrons create resonance inside the magnetron in the cavities, and this is at 2.4GHz, fed out via a tap in the one cavity via a feedline to the end cap, where it is introduced into the waveguide cavity at the top, and from there through a RF transparent window into the large oven cavity. the magnetron will start oscillating at some voltage between 3-4kV, absorbing the energy out of the capacitor and transformer, so while it only is being turned on for a half cycle, the energy is basically doubled, as the other half cycle is storing energy to be used then. No Beryllium oxide in the commercial microwave magnetron, it is way too expensive to use in that cheap product, so instead it is either white, pink or purple fused aluminia, aluminium oxide crystal, otherwise called when the crystal is large and not a powder, ruby. Here just a high temperature ceramic insulator. But the magnetron is still dangerous, the 2 strong magnets can shatter if slammed together, and they will attract small metal dust to them. Also never run a microwave with nothing in the cavity, the energy not absorbed in the load is reflected back into the magnetron, heating it up a lot more thna normal, and eventually the magnetron will become too hot, and the thermal cutout for the magnetron will turn off the microwave, or the transformer, till it is cool enough, and another turns off the microwave if the cavity itself gets too hot.

[@nixdorfbrazil]

Two of my favorite youtubers in a great collab! What a great week! Thanks God! Although Medhi isn't a little crazy. He's COMPLETELY INSANE! Lol. Love you guys.

[@jamescomstock7299]

Firmly second this!

[@arthurmee]

Me too.

[@FridayHouseXYZ]

I was thinking the very same thing lol!

[@davemarm]

Think you misspelled "Mehdi"

[@arthurmee]

@@davemarm yes you're right. I'll correct it. Thanks.

[@Gurux13]

50% of the energy is not really wasted, though. It's just not used, but it doesn't get turned to heat or anything. In other words it doesn't end up in your energy bill :)

[@ScienceAsylum]

I clarify in the pinned comment.

[@Gurux13]

@@Kevin-mp5of they are unlikely to do that. Also, even in terms of apparent power it's not 50% wasted :)

[@extremawesomazing]

Love the cameo and really cool visuals! Thank you thank you!

[@bradleyfitzik2447]

Nice to see you and Mehdi working together 💪

[@lochinvar00465]

The power of the magnetron can be changed by changing the value of the capacitor. One time I had to replace the cap on a microwave and the only available cap was a bigger value than the original. As a result I found that the power of the oven was dramatically increased to the point that a cup of tap water would boil in 1 minute and 35 seconds instead of the expected 3 minutes. More, by using a smaller cap, the power can be reduced. As mentioned in the video, only if you are properly trained should you ever work inside the microwave on its circuits. I'm a radar tech and am well aware of the dangers around such circuits. Please be careful making your own mods.

[@NealIRC]

Are microwaves proprietary now? Meaning a microwave made by a company, can only use parts also made by the company? Like magnetrons, capacitors, transformers, etc.

[@JM-jc4hm]

When the capacitor is shorted out at 3:10, something DID happen. The audible click was very likely the sound of electric discharge via an arc to one end of the pliers just before contact was made.

[@AdamV20]

0:01 Me who dissasembled 4 microwave ovens: whats the problem?

[@ScienceAsylum]

You must be trained.

[@luudest]

There is a micro wave (called „Dialog oven“) ait works so precisely it is able to cook fish within an ice block.

[@odysseus9672]

Re: not talking about angular diameter turnaround. I think it's less that we perceive it as an obstacle, and more that they think people will find it to be an uninteresting detail that they can't prove with pretty pictures. Basically, it contributes to cosmological surface brightness dimming, and statistical statements about the size of galaxies compared to what we expect. Without context about surface brightness being constant in a non-expanding universe, or comparative measurements of galaxy sizes, it just isn't as easy to grasp in a single picture as "further things look redder".

[@ScienceAsylum]

That makes sense. Scientists don't always have a good perspective on what the general public will find interesting.

[@demetriusjohnson5358]

Your videos are always great. I bought your book! I live in wyandotte so ik about downriver so awesome you are from here! Keep up the good work and I will hopefully be Patreon supporter really soon when i finish school!

[@ScienceAsylum]

Thanks for buying the book! I hope you like it 🙂

[@randycarter2001]

Not a bad description. It turns out the positive half cycle is used to boost the negative half cycle so the energy isn't lost. The magnetron uses a negative 5,700 volts not positive. That particular tube (yes, it's a vacuum tube) doesn't like continuous operation. It likes to be hit with pulses of energy. 60 times a second, bam a new 5,700v pulse.

[@MachiningandMicrowaves]

Huge fun, and with Mehdi as technical expert, what's not to like? Leakage inductance in those transformers is the key design element that helps control the peak current without resistive loss. That's the really clever bit of the ultra-simple design. How magnetrons work is like blowing air across the top of a bottle to make a musical note, but using electrons in a magnetic field and "blowing" them across the edges of lots of metal "bottles". Total magickery.

[@MachiningandMicrowaves]

@@gags730 The history of development of the cavity magnetron is fascinating, the basic principle was understood from the early 1900s but the compact multicavity magnetron was developed with the aim of making an aircraft- based radar. The Tizard Mission followed the surge of development by the UK General Electric Company and the 10 kW version was one of the technologies shown to the US committees in the search for a manufacturing facility and finance. I should do a video about the history and tech detail, but I'm a bit tied up with my work on the Great Seal Bug project for BBC television and projects on Gyrotrons and a quadrupole mass spectrometer.

[@gary.richardson]

I'd love to see a video produced, similar to how Jeremy Fielding does on his channel. If you haven't seen his channel, he has put together some good explanations geared toward the non-technical

[@MachiningandMicrowaves]

@@gary.richardson Jeremy is a brilliant presenter and engineer, I've watched his channel since he started and he's definitely a role model.

[@thezood]

I am now thankful that me and my friend never realized the microwave weapon we planned to build from a microwave oven back in the days.

[@sirellyn]

Yep, now I'm even more terrified of microwaves.

[@ScienceAsylum]

There's a reason they usually have a warning label telling people not to open the casing.

[@jasonremy1627]

A Collab with Electroboom? Christmas has come early this year.

[@Debraj1978]

There are multiple application in our home appliances where half wave rectifier is used, as it is cheaper. Dishwasher is a common application, as the motors are low power ones. If anything is not wasting energy (not heating up), then, there is always an application for it somewhere -- could be a half wave rectifier, or incandescent bulb.

[@playgroundchooser]

I got really scared for Experiment Clone for a bit there. 😲 I'm glad it all worked out. This was so cool Nick!

[@ScienceAsylum]

ElectroBOOM, saving lives.

[@VenomDDD]

1st video i stumbled upon from your channel. Sympathic host, funny and yet educating. Yeah that's an insta sub. Much love.

[@joeymccall7664]

My two favorite youtubers finally together spreading knowledge. Dope!

[@calicoesblue4703]

2 of my favorite channels coming together for this. Awesome guys😎👍

[@gothesouthway]

He said a half wave rectifier waist half the wave and was less than 50% efficient. It's not shunting half the wave, it;s blocking half the wave. It's not waisted (dissipating energy as heat), it's just not using half the wave. As for efficiency, the only loss is in the transformer and resistance loss in the wire. There is a energy loss through the diode, but it's tiny. you're looking at a ~90% efficiency, not 40%.

[@Basement-Science]

You are correct, except that the magnetron actually wastes a lot of energy , leading to a total efficiency of around 65% or so.

[@ScienceAsylum]

Thanks for the correction. I clarify in the pinned comment.

[@VoightKampf]

@6:41 I had to laugh. This reminded me of my high school electronics class when I bread boarded a circuit with a zener diode with the polarity backwards.

[@Ruddigore]

A great video and a forceful reminder to me to never, ever take a microwave oven apart. Loved the collab.

[@GoatPopsicle]

This was a perfect time for that collaboration. It’s how I originally found your channel. Now I’m back after taking apart an older microwave, and finding out it was old enough to contain beryllium. Thankfully my local (public) electricity provider takes dangerous goods at no cost.

[@N0Xa880iUL]

What a great Collab!!!! Lovely 😍

[@ethanrowlette9912]

this video earned you a rung bell keep up the explanations about electrical waves and circuits that manipulate them its such and under discussed topic for obvious reason most people cant even understand it let alone break into easily digestible bit like this

[@ScienceAsylum]

Thanks! Glad you appreciate it.

[@thomasmogensen1]

Great video, learn some new stuff, really enjoyed the circuit tour and seeing the scope in use. Just really like electronics 😎👍🏻👌🏻 Thanks Thomas Mogensen

[@wesshepard]

Thanks for another super fun, Awesome video, Nick!

[@PhantomMarquis]

Having learned a good chunk about sound-waveforms, I find other varieties of waves fascinating-props to your little-craziness for this demonstration!

[@dahlavibez5726]

Electro booms slap on the head was hard man is that a red spot ??? 🤣 Educational content for sure and nice volume voice n all 🙏🙏

[@lakshman587]

4:45 the great realisation 😂😂

[@allmycircuits8850]

Another interesting fact: half-wave doublers require 2 diodes to work, but microwave oven has only one. The other one is magnetron itself! It's good old vacuum diode in some sense!

[@ScienceAsylum]

Interesting! Might include this detail in the magnetron video I'm working on (if I find a source I can list for it in the video description).

[@k7jeb]

I was going to point that out about the magnetron but you got here first. The magnetron *is* a diode and would just act as one, but the magnetic field running through it (from the big magnet not mentioned) causes the electrons to swirl around as they go from cathode to anode and impinge on small cavities bored into the anode of the tube, exciting them to resonate at 2.45 GHz and heat up your coffee cup (or whatever).

[@patrickhayden7206]

How did you make this video, colab with Mehdi, talk about rectifiers and not once did we ever hear, "FULL BRIDGE RECTIFIER!" ? :-) Great video.

[@hoggif]

I'm sure it has been cut out. I find it too unlikely it never happened! :D

[@omsingharjit]

Same Question A fool bridge Rectifire

[@tyronefrielinghaus3467]

Looking fwd to video on how magnetrons emit em waves...and the voltage and current requirements for them to work.

[@badmeatbrowniesthoughts1327]

Always good to hear from Nick. Great stuff brother 👏

[@jmmahony]

I'm amazed you did that whole video without once having Mahdi shout "FULL BRIDGE RECTIFIER!!!"

[@g00glian0]

That was an excellent video and cleared up a few things I did not fully understand. Would love to see more electronics like this.

[@benjaminzacharko8740]

Never realized it was a half wave doubler! You learn something new every day.

[@harthur2010]

Awesome video! Loved the cameo and how your lower voltage circuit matched the microwave one.

[@ScienceAsylum]

Safety first 👍

[@harshsharma7154]

Hey 👋 nick! Thanks for these wonderful videos.

[@JonathanFisherS]

Love your channel! No plans to ever take one apart but I appreciate everything you put into this vid!

[@ScienceAsylum]

Now you don't have to 😉 because I did it for you.

[@Saitama62181]

I didn't know all that was going on inside my microwave. Thanks for rectifying the situation! 🙂

[@ScienceAsylum]

Good pun 👍. Glad I could enlighten you.

[@TimmyBoja]

6:25 - Open circuit voltage is always going to be higher than the operating voltage. I measured a SELV shaver point before and called up the manufacturer to complain - but it’s dips down to a rated voltage under load.

[@ФедяКрюков-в6ь]

Trained professional can always be recognized for using professional tools. Like pliers attached to a wood plank with duct tape, for example

[@ScienceAsylum]

😂

[@RichardJohnson_dydx]

Grear video. For once, this is a video topic I understood completely. If there's one thing one of my circuit classes' professor drilled into us, it was that diodes are not loads.

[@sabarishr381]

Thanks for the beautiful video ! Learnt something new today !

[@ScienceAsylum]

My pleasure 🤓

[@punditgi]

These crazy videos are always amazing and fun! Keep 'em comin'! 😃💯💫💢💖💥

[@emuevalrandomised9129]

Science Asylum and Electroboom? This can't get any better!

[@dedamarsovac]

Fun fact, it's not even half wave. Try measuring the input current on the oscilloscope. The microwave utilizes power equally from both the positive and negative half of wave. On the positive half-wave, it draws power to charge the capacitor, and then on the negative half-wave it draws the same amount of power to power the magnetron while also discharging the capacitor. The grid is loaded full-wave, but the magnetron gets the half-wave pulses. The capacitor just transfers energy from one side to the other side of the wave.

[@alejrandom6592]

Holyshit holyshit holyshit the crossover I didn't know I needed

[@alejrandom6592]

And I'm still excited

[@hogandromgool2062]

Mehdi is doing a lot of consulting this year. Good for him!

[@homersimpson1933]

Nice to see you covering the Doubler. I don’t think I’ve seen someone explain the difference in the voltage you can get simply by changing where you put the load in that simple circuit since my EE classes in college… 30+ years ago. Nice!

[@chotuminu902]

the legendary collab i was waiting really for😄😄😄

[@stonelaughter]

Now we need to know how a magnetron works!

[@ScienceAsylum]

Working on it 🤓

[@threeMetreJim]

The real reason for your microwave wasting approx. half it's power is that the conversion of electricity into 2.4GHz is not very efficient (the magnetron); this is the reason for the magnetron having fins, and a cooling fan blowing air through them.

[@ScienceAsylum]

I'm working on the magnetron video already. I just didn't include it here because this video already had enough info in it.

[@theinterruptedlife1783]

WE NEED MORE OF YOU AND MEHDI

[@Samien]

Congratulations 600K 🎉 onwards & upwards 💪🏻

[@ScienceAsylum]

Thanks!

[@KyleJMitchell]

ElectroBOOM in the thumbnail + "half-wave rectifier" name card = me bracing myself for the next parts of the video.

[@sussus4914]

oh man i don't always watch every video you make but this one was so entertaining!😅

[@viralsheddingzombie5324]

IF you thought Nick was crazy...wow...that ELECTROBOOM guy is off the hook.

[@WouterVerbruggen]

Did you measure the 15 V on the transformer unloaded? (i.e. open circuit, only multimeter attached) If so that's the reason its (a lot) higher than 12 V, the voltage will drop to around 12 when it's loaded around its design load.

[@volvoxpl]

Im confused. It seems that half-wave doubler does not waste energy (at least noting near 50%), or i'm missing something?

[@eDoc2020]

You're not missing anything. Read the pinned comment.

[@sivalley]

That capacitor still had a significant charge! That loud tick when you shorted it with the pliers was a good arc.

[@awaisislam9449]

Seeing Mehdi always bring joy... ⚡⚡⚡ The biggest electrician...

[@netsplit64]

Good you made a model. People were making devices to burn arcing patterns into wood using salvaged microwave transformers and the injuries were pretty bad. Best not to mess with them.

[@scottfranco1962]

Small nit: that cellphone converter you held up is NOT transformer based. Rather it has a switching power supply. That's why it is so small and light.

[@ScienceAsylum]

I'll admit, I based that statement on my knowledge of those bulky phone chargers from the 90s. I wasn't aware the design changed.

[@rayoflight62]

There is a transformer inside, to separate the main from the output. It just doesn't operate at 60 Hz, but at 100 KHz, so it can be very small and convert energy very efficiently...

[@keysersmoze]

@@ScienceAsylum I just assumed they became switching power supplies from their light weight for their power rating. Pick one up, hey Where did all the Iron and copper go?

[@peterdonnelly1074]

It still has a transformer, albeit quite a bit smaller

[@martinpayne2934]

@@keysersmoze The other clues are the high pitched whistling sounds they make, the weird vibration you feel if you run your finger along a metal surface on the device being charged, and the electric shock you get if a single hair on your finger is touching a metal surface on the device being charged!

[@richardspectacular5327]

10:31 I'm going to guess that the small amount of clipping is due to the diode forward voltage drop (typically 0.7V), and is not caused by the load. Nice video!

[@dallenthompson483]

Just to add a little detail to the circuit :) It looks like the diode is usually connected between the capacitor and chassis. This allows for an ac current applied to the fillament of the magneton to be DC biased to high voltage (think hot filament electron emission). The electrons dump into the shell of the magnetron, back to ground. A video detailing the magnetron would be awesome! They're ingenious little vacuum tubes :)

[@ScienceAsylum]

All the big components are grounded to the chassis. I didn't realize there was a sneaky reason for that.

[@AlexandarHullRichter]

@@ScienceAsylum I was always nervous about letting metal objects touch a microwave casing while it was on (careful not to put a fork or spoon on top of the microwave while waiting for my lunch to cook, for instance). Now I guess have a really good reason for that.

[@PlatypusPerspective]

@@AlexandarHullRichter The casing of a microwave oven is simply an earthed metal box. There's no difference between it and any other grounded metal surface - if the microwave is next to a refrigerator, there would be no difference between placing a fork on the refrigerator or the operating microwave.

[@woll3Y]

The "coming soon" explanation of the 2.4 GHz solid state magnetron should also cover why they moved away from the ~900 MHz vacuum tube style. (Running the oven empty creates an impedance mismatch that could start a fire and/or break the glass) Would also be great to see how @The Science Asylum explains the quarter wave choke energy seal that works even if you hang a kitchen towel on the door before you close it.

[@PlatypusPerspective]

@@woll3Y I've tried to follow the line of your post, but I'm not sure I get what you're saying. Either 900MHz or 2.4GHz are used depending on what will be most effective and practical for the application, more than because of any particular type of technology available. The physical constraints of the wavelength, with the resulting mechanical sizes, and the inevitable difference in load energy absorption and depth of penetration govern the suitable usage. Because of this, 900MHz is usually used in large equipment in commercial and industrial arenas and at high powers, where improper usage could certainly produce spectacular results.

[@altxyz]

Half wave rectifiers dont "waste" half of the energy. The only waste here is forward voltage drop which could be 10V at these HV diodes.

[@ScienceAsylum]

I've pinned comment with clarification.

[@altxyz]

@@ScienceAsylum "By saying half the energy is wasted, I only meant that it was available but unused. In other words, the device doesn't take full advantage of what the wall is providing." Sorry, but your clarification makes even less sense. I measured my microwave oven's power consumption with a power meter. It was ~1400W at full power and the cosfi was around 0.95. The outlet on the wall provided 1400W, and the microwave oven used that. With a power factor of 0.5, what you said would make sense: the wall can provide 2800VA, but the microwave only use 1400W. But as i said, the power factor was 1. I think you need to clarify what you are talking about. Power factor? Rectification efficiency? Transformer utilization factor? Or an efficiency of what?

[@altxyz]

Try this. Use a single diode (half wave rectifier) and a capacitor to produce dc voltage. Since the transformer utilization factor for this setup is around 0.4, you need a 2.5 times bigger VA rating transformer than your dc output power. Yes that might match with your concept with the "available but unused" power. But what do you think, is the transformer in your microwave oven rated for 2000+ VA?

[@paulmichaelfreedman8334]

The reason a transformer rated at 12 Volts is usually around 15V is because it allows for a full bridge rectifier and a voltage regulator, which contain diodes and thus always have some voltage drop.

[@exscape]

Also the open-circuit voltage will be higher than at load.

[@Basement-Science]

Not quite. The real reason is that it's rated voltage is at the rated current/power, because especially with small transformers like this, their voltage drops significantly with load, because of copper losses in the very long thin wires.

[@NealIRC]

@@Basement-Science right diodes do not change the voltage drop much. Are there any things that can cause the multimeter to read a lower voltage instead of higher?

[@Owen_loves_Butters]

@@NealIRC Diodes so cause a not insignificant voltage drop because of the PN junction.

[@analoghardwaretops3976]

Such transformers..(low cost ones)..are energy inefficient...for the simple reason of cost...these are said to have poor " LOAD REGULATION " .. A transformer with good load reg.would probably have... 1) higher ampere (copper..but not CCA) wire gauge in both pri & sec.... 2) thinner and better grade ( low eddy loss) laminated magnetic core material.... this may involve using the next larger core size......hence the cost is kept down by smaller manufacturers....... Load regulation.. in % , .. for (the sec. winding under test)...is usually measured as ... { o/p volts @ rated load ÷ o/p volts @ no load}×100..and keeping/ensuring same value of input volts.(pri.)...in both load & no load measurements. The value closer to 100 the better the regulation...

[@entropyachieved750]

Great team up! 2 top channels

[@youdontknowme5969]

Happy Thanksgiving! ps: I know Mehdi's Thankgiving was last month

[@ScienceAsylum]

Thanks! Right back at you (if you're in the US). I was telling Mehdi I was hoping for a Thanksgiving week upload and then realized his was a different week.

[@dabyd64]

From AC mains view, it's using both half-waves, first one charges the capacitor up, second one is pushed into the magnetron with the added energy stored in the capacitor. It's the magnetron what works only in "half-wave" mode. I guess it would work at 100% if using a 5KV secondary, but the transformer would be larger to accomodate twice the wire turns, also isolating 5KV would be harder, requiring oil bath/resin encapsulation, probably the only reason for this is to lower the costs.

[@eDoc2020]

The capacitor in the doubler also helps to limit the current.

[@mattfanslow]

It would have been interesting to try a capacitive probe near the transformer. This would have protected you and the DSO, but the amplitude may not have been perfectly accurate. Much of this is used on automobiles for charging batteries or even ignition (spark). Very well done, sir.

[@AlexandarHullRichter]

I haven't heard of anyone checking batteries with those, since a basic multimeter is usually sufficient, but that type of probe is used to detect ignition timing in cars that have distributors.

[@drescherjm]

0:08 Yes I have done so to replace the safety switches when they were faulty causing the microwave to not turn on at all. And yes I know the capacitor can easily kill you so I made sure that I deenergized that first. In the unit I worked on there are three 15A momentary switches that are activated when the door is opened for added redundant protection against failing in the energized position. There is also a relay that is activated when all 3 switches are in the proper position. 2 of the switches have wires on both the NC and NO positions of the switch.