Ask Fran: Vacuum Fluorescent Displays, Microwave Radiation, & The Ecliptic.

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  • เผยแพร่เมื่อ 25 ธ.ค. 2024

ความคิดเห็น • 88

  • @eDoc2020
    @eDoc2020 3 ปีที่แล้ว +22

    If anybody wants to drive a VFD without wiring up tons of transistors they can also use a chip like the HV5812. It's like a 74HC595 except the outputs can drive up to 80 volts. It has 20 outputs so you probably only need one chip to drive all the grids and anodes. It's also relatively cheap ($2.66 in single qty) in DIP package.

    • @NivagSwerdna
      @NivagSwerdna 3 ปีที่แล้ว +3

      +1 for the HV5812; I use one of these to drive my IV-18 VFD clock.

    • @mikegLXIVMM
      @mikegLXIVMM 3 ปีที่แล้ว +2

      Good tip, thanks.

    • @jkmacgyver
      @jkmacgyver 3 ปีที่แล้ว +2

      Its also worthy to note that the filament heaters should be driven ideally by AC for even brightness across the display

  • @Michael.Chapman
    @Michael.Chapman 3 ปีที่แล้ว +10

    You’re a great teacher Fran and seem full of more obscure details relating to your topics 🙏🏼

  • @brucemillar3015
    @brucemillar3015 3 ปีที่แล้ว +2

    Did you know, if you stop a microwave oven by hitting the open-door button, you get a full blast of high-power microwaves right out of the door towards you. Even though opening the door cuts the power to the oven, the power supply high voltage persists for a while and the magnetron heaters stay warm for a while also. This results in a powerful microwave emission from the open door for a second or so. Friendly advice: Never stop your microwave oven by opening the door. Allow it to stop automatically or hit the 'Stop button first; Radio Astronomers will love you for this.

  • @anotheruser9876
    @anotheruser9876 3 ปีที่แล้ว +12

    Place marshmallows in a shallow dish (so it completely covers the bottom) in the microwave without the rotating plate and let it run for about 10 seconds. Melted parts will appear in the marshmallows and the holes are 1/2 wavelength apart. Now, check the oven for the frequency and together with the measured wavelength (2x distance from hole to the nearest next hole) you can calculate the speed of light.

    • @uwezimmermann5427
      @uwezimmermann5427 3 ปีที่แล้ว +5

      a bar of chocolate also works nicely here

    • @allanrichardson1468
      @allanrichardson1468 3 ปีที่แล้ว +3

      And then eat the evidence! Add the chocolate and you have “s’mores!”
      But no peanut butter. The oil absorbs microwaves so well that it overheats. The protein particles then clump together, turning creamy PB into “crunchy,” and due to the low water content, heating doesn’t stop at 100 C. I warped a soft plastic jar trying this!

    • @PaulLemars01
      @PaulLemars01 3 ปีที่แล้ว

      @@kaitlyn__L Just cracked a soup bowl base doing this very thing.

  • @davidbarts6144
    @davidbarts6144 3 ปีที่แล้ว +1

    The reason a grid in the window blocks microwaves is the same reason why the 70 cm ham band is better for penetrating inside skyscrapers than the 2 m band. The distance between the (steel-reinforced) floors and ceilings is around 2 m so the longer radio waves have trouble penetrating.

  • @islandhopperstuart
    @islandhopperstuart 3 ปีที่แล้ว +2

    Fran, a microwave oven heats because the emission frequency - 2.45GHz - is the resonant frequency of the Hydrogen bond in water, and when so excited, the water heats.

  • @CARLiCON
    @CARLiCON 3 ปีที่แล้ว +6

    Love the new format...kind of a encyclopedia bri-fran-nica type of thing. Well done!

  • @angrydove4067
    @angrydove4067 3 ปีที่แล้ว +14

    Keep the answers coming, I enjoyed them today.

  • @tony_w839
    @tony_w839 3 ปีที่แล้ว +7

    I have a story I was told, from when I started work 50 odd years ago at a Government research place. Microwaves work by vibrating the water molecules inside whatever is being cooked. Radar uses microwaves that are focused and a technician lost his arm as he was working his arm was in the beam. He did not feel his arm getting hot as body temp sensors are towards the skins surface. Very sad, but his arm died from being cooked.

    • @stephen1r2
      @stephen1r2 3 ปีที่แล้ว +3

      Any number of birds die occasionally in front of long distance transmission towers. (those horn-of-plenty shaped ones)
      So if you want to stop bad press, scarecrows and noisemakers are employed to keep birds from stopping at the nicely warm spot for the night.

  • @Rob_65
    @Rob_65 3 ปีที่แล้ว

    7:55 it's the magic of power and pointing it at a specific point. Water can cut a lot of materials but we all wash our hands with that same type of water and I will happily walk outside in the rain without being scared of the rain tearing me to pieces. But I somehow love your explanation more ;-)

  • @mattwillis3219
    @mattwillis3219 3 ปีที่แล้ว

    Wisdom is an understatement with this one.

  • @mikegLXIVMM
    @mikegLXIVMM 3 ปีที่แล้ว

    I used a ULN2803, which contains 8 Darlington transistor drivers to drive the segments.
    A VFD is one of the few vacuum tube applications left.

  • @Lethgar_Smith
    @Lethgar_Smith 3 ปีที่แล้ว +3

    Most solar systems form into roughly a disk shape is due to the spin of the star around which they form.
    When an object is spinning it will throw off portions of itself in a plane perpendicular to its rotation.

    • @ewxyzzy
      @ewxyzzy 3 ปีที่แล้ว

      The accretion disc is a disc because angular momentum is conserved. Motion perpendicular to the disc of individual objects was lost through interaction but the net rotation of the original cloud remains. The result is that not only the solar system is a disc but all the planets rotate in roughly the same direction. Objects that don't (like Venus) need some extraordinary explanation like a collision.

  • @SlyPearTree
    @SlyPearTree 3 ปีที่แล้ว +1

    I've often wondered why we should not run a microwave while it's empty but other things always take precedence when I'm in a researching mood. Thanks for the explanation.

    • @RichardPolhill
      @RichardPolhill 3 ปีที่แล้ว

      Two main reasons. Firstly you can create hot spots which can cause damage to the interior and it's also possible to generate a standing wave that will burn out the magnetron.
      It's generally not a good idea, but not, like, the world will end. You can damage the oven. I suppose, in theory, it could eventually cause a fire but I'm not sure how likely that is.

    • @allanrichardson1468
      @allanrichardson1468 3 ปีที่แล้ว

      It’s better not to try, unless you’re the Quality Control lab in a manufacturing company. Or Consumer Reports.

  • @samuelrieder5480
    @samuelrieder5480 3 ปีที่แล้ว +1

    Thanks for your reply.

  • @thejll
    @thejll 3 ปีที่แล้ว

    The focus with a lens explanation is good!

  • @featheredskeptic1301
    @featheredskeptic1301 3 ปีที่แล้ว

    It may also be possible to use something like ULN2003 darlington transistor array chip instead of individual transistors for driving a vfd. Connect resistors from high voltage to the collectors and drive the anode from the collector outputs of the chip. Input logic level 1 on the input of the chip to turn off a segment or logic level 0 to turn it on. Basically, an array of inverters that switch high voltage to the anodes of the vfd. That chip holds up to 50V, so it should be good enough for most vfd types. For multiplexing you can use the the same type of an array for driving the grids.

  • @cat637d
    @cat637d 3 ปีที่แล้ว +6

    Very informative and enjoyable, great lead in and out!

  • @Enigma758
    @Enigma758 3 ปีที่แล้ว

    4:32 Doesn't an emitter follower have unity voltage gain, so you couldn't get 24v considering it's being driven from an arduino? I think you may have intended it to be common emitter.

  • @lorenzoboyd6889
    @lorenzoboyd6889 3 ปีที่แล้ว

    My circa 1982 Sharp microwave oven has a 'hold' function. When setting a cook function, I proceed it with four seconds of hold, followed by the desired cook time. I then press 'start', and move a few feet away, invoking the inverse square law. (I operated radar in the Navy).

  • @AJ-bt1mj
    @AJ-bt1mj 3 ปีที่แล้ว +5

    Love the q+a Fran! Really enjoyed the live stream a couple weeks ago!

  • @markscheutzow3446
    @markscheutzow3446 3 ปีที่แล้ว

    Hello Fran,
    If you have a VFD operating, but the display blanked, in a very dark room, you can, up close, see the cathodes glowing a dull red.
    😎

  • @paulstubbs7678
    @paulstubbs7678 3 ปีที่แล้ว

    Wow, from creation to now, with a VFD thrown in.

  • @SeanBZA
    @SeanBZA 3 ปีที่แล้ว

    VFD interfacing is one of those things where you have very odd voltage needs. Easiest way is to use CD4049/Cd4050 level translating buffer/inverters, so that you convert your 5V drive to a 15V rail, powering the 4049/50 off of a 15V rail. This is also the VFD anode and grid voltage, and the cathode and common heater is then powered from a small negative voltage source. most common is a -5V rail and a heater supply running off a small 3VAC centre tapped winding off a transformer. Heaters are run till hot, they should be barely visible as light emitting, looking right up at the display in a nearly totally dark room, any brighter and they have a very short life. This gives a 20V operating voltage, which a lot of VFD units are happy with, though often the larger ones need a -12V supply instead of 5V, as they run off 27V for full brightness, but will be perfect at lower voltages, just dimmer and perhaps spotty display segments. 15V swing on the anode and grid is fine, and there will not be much ghosting.
    Otherwise if you want to use discrete transistors the heater is connected to ground, and you use a PNP transistor from the 20-30V positive rail to feed the grids and anodes, using NPN transistors fed from the TTL level driver, via current limiting resistors, to provide anode and grid drive. you will need pull down resistors as well for anodes and grids, but those can be 100k or higher. Otherwise open collector 30v rated TTL, with around 4k7 pull up resistors to 20V, and accept your power dissipation in the resistors is going to be higher than the display power as you have to turn the transistor on to turn off the display anode or grid.

  • @uwezimmermann5427
    @uwezimmermann5427 3 ปีที่แล้ว +1

    Hi Fran, it's not that infrared is particular good at transmitting heat, it is just bad at everything else! 100 W of visible light, 100 W of infrared and 100 W of microwave are all about the same, apart that the absorption happens at shallower and shallower depths. Visible light starts to also have the ability to influence chemical reactions like vitamin D production in mammals, photosynthesis, analog photography.

  • @tonyturtle5805
    @tonyturtle5805 3 ปีที่แล้ว

    maybe if we put a magifying glass over solar panels we could get more energy from the solar panels ? this was a great video thanks fran !!

  • @cklinejr
    @cklinejr 3 ปีที่แล้ว +1

    I really like this new Q&A thing. Very enjoyable!

  • @750kv8
    @750kv8 3 ปีที่แล้ว

    03:31 - Actually the little cathode filaments do glow very faintly, it's only noticable if you look at them very closely, and in the dark.
    15:16 - They seem to have found the remnants of the proto-planet Theia, that collided with the proto-Earth 4.5 billion years ago, in the lower mantle.

  • @michaelfrench3396
    @michaelfrench3396 3 ปีที่แล้ว

    You are one groovy lady!! 👍😀😀 I love these videos on antique display techniques!!

  • @maxusboostus
    @maxusboostus 3 ปีที่แล้ว

    As a child I had one of those VFD space invader clones called Astro Wars, and in certain parts of the game you could see all 4 heater wires glowing very clearly. Might not have been doing it much good.

    • @Wenlocktvdx
      @Wenlocktvdx 3 ปีที่แล้ว

      I have one I found recently at a thrift store. They’re so cool

  • @Cristian.Cortez
    @Cristian.Cortez 3 ปีที่แล้ว

    VFDs my favorite!

  • @gabest4
    @gabest4 3 ปีที่แล้ว

    The microwave oven window has another interesting property. You can only see the food inside if you continuously move your head sideways.

  • @menadue
    @menadue 3 ปีที่แล้ว +1

    You can also use the MAX6921. It has serial inputs so not many GPIO lines are used up. It handles the high voltage driving. The filament drive is meeded, and a high voltage supply for the MAX6921. Here's a couple of projects I did with it:
    th-cam.com/video/gca-PwKa4d8/w-d-xo.html
    th-cam.com/video/XzfspKhKC18/w-d-xo.html
    The Arduino can also drive it.

  • @Shaun.Stephens
    @Shaun.Stephens 3 ปีที่แล้ว

    Thanks Fran, I learned a few new things.

  • @nukeum9535
    @nukeum9535 3 ปีที่แล้ว

    great vid fran. highly enjoyable. get to learn about new things.

  • @elanman608
    @elanman608 3 ปีที่แล้ว

    Question? Currently I am thinking of and working on things where the abreviation VFD would mean Variable frequency drive. I was following what you were saying about Vacuum Flourecent Displays but every time you quite legitemately called them VFDs my train of thought derailed and I had to go back.
    Does this sort of thing happen to anyone else?

  • @ZylonFPV
    @ZylonFPV 3 ปีที่แล้ว

    This is a great video series, good answers and I paid full attention!

  • @itdtv2510
    @itdtv2510 3 ปีที่แล้ว +1

    Thank you, Fran!!!

  • @frankowalker4662
    @frankowalker4662 3 ปีที่แล้ว

    Can't wait to see the VFD (Volunteer Fire Department ? LOL.) projects.

  • @JohnKelly2
    @JohnKelly2 3 ปีที่แล้ว

    As a musician pedal builder, what's your opinion on the NuTube?

  • @paulbennell3313
    @paulbennell3313 3 ปีที่แล้ว +7

    The things this lady knows. That's a big old brain!

    • @WeedMIC
      @WeedMIC 3 ปีที่แล้ว

      Not old in any way, tuned.

  • @grabo454
    @grabo454 3 ปีที่แล้ว

    I'm good, Fran. How are you? Thanks for asking and thanks for doing these videos. Keep up the good work!!!

  • @roxypda
    @roxypda 3 ปีที่แล้ว

    Great series Fran!

  • @shockwavecity
    @shockwavecity 3 ปีที่แล้ว

    Fran: Have you ever checked out the Korg Nutube? kind of a VFD based audio tube. Gimmicky, but neat to fool around with.

  • @mikek5633
    @mikek5633 3 ปีที่แล้ว

    Love these segments !!!

  • @nor4277
    @nor4277 3 ปีที่แล้ว

    Radio shack use to sell a fluorescent display it was a clock ,you had to ac nd your own buttons and power supply.

  • @cgoad
    @cgoad 3 ปีที่แล้ว

    Hi Fran. I like this Q&A format. You are very clear in your answers. Bring on episode 2! (And more?)

  • @InssiAjaton
    @InssiAjaton 3 ปีที่แล้ว

    It might be useful to bring in some power comparisons. My home microwave oven uses 900 watts of power. There are losses in the conversion to microwaves, as well as a need for a fan and plate rotation. I don't know exact numbers, but let's guess you might get 500 W into your cup of water or bowl of soup. If you continue long enough to boil the water, the steam will heat the oven door (and ventilation passages). But what might come out through the front? In the early days of marketed microwave ovens there were reported leaks AROUND the front door and there were detectors sold for checking that leakage. I think those hand held detectors cost more than the oven. I have not seen those advertised for years now. But as far as I remember, they were indicating microwatts per square centimeter, i.e. one millionth or less of the magnetron delivered microwave power. Now, your cell phone power radiation is roughly on the same order of power that the leak detector was built to detect. Then, let's go to the opposite direction. Big commercial kitchen microwave ovens may be 2000 to 4000 W. Maybe you have noticed they toast the cheese in your sandwich in just 10 to 15 seconds. Still something you are not required to through lengthy safety trainings to be around. Then we take the next step -- weather radars. Unlike your phone or a microwave oven, the radars send out highly focused beams at million watt levels. You can bet that the people operating those radars are not just picked in from the nearest street. Those beams are detectable when they get reflected from rain clouds. The weather radar receives those reflections through the same big parabolic antenna that sent the beam. But you can receive reflections from occasional passing aeroplanes with just a small 3- or 10-gain antenna and a spectrum analyzer. Have done that. Like the microwave ovens, your home WiFi used to operate at the frequency band of 2.4 to 2.5 GHz, which is allocated for miscellaneous industrial and other multi-user applications. You don't get a private frequency, but have to live with whatever noise other users send your way. The weather radars operate around 5.5 to 5.8 GHz. Then there are military radars that operate as they please at whatever frequencies they want, or at least that is how it appears.

    • @AndrewGillard
      @AndrewGillard 3 ปีที่แล้ว +1

      A minor query regarding your otherwise fine comment - my intention isn't to say "omg you're wrong", I promise! :)
      Are you sure your home microwave oven *uses* 900 W?
      As you and Fran noted, they're not very efficient appliances, but my understanding is that the headline power rating of microwave ovens is the *output* power (at least here in the UK), with them drawing a lot more than that from the mains supply.
      I actually measured my microwave oven's power draw this evening for unrelated reasons.
      Mine is rated 800 W, but when cooking at full power it was using around 1400~1500 W - and 400~500 VAr (reactive power), incidentally! 😅
      I realise it's possible that your microwave oven is lower power than I've ever come across (or maybe mine is faulty!), but you may find that yours actually uses somewhere around 1600 W :)
      And despite that efficiency not being great, it still seems like it's much less energy-intensive to cook something with my microwave oven than with my regular, fan-assisted electric oven, where I'd have to run a 1800 W heating element for almost 10 minutes *just to pre-heat the oven*, by which time the microwave oven could have already finished cooking the vast majority of things I'd consider using it for - and with 20% less power!
      (Obviously I'm aware that microwave ovens aren't suitable for everything. I don't cook pizza in a microwave, for example. My point is just that efficiency is relative, and my microwave's 55% efficiency is pretty good compared to a regular oven! :))

    • @RichardPolhill
      @RichardPolhill 3 ปีที่แล้ว

      @@AndrewGillard The power rating of a microwave (the one on the front) is the rating of the magnetron, effectively how powerful the output is. They use more than.
      An interesting fact about microwave ovens is that they use a frequency that is chosen to absorb about 2-5cm into food. If they choose a frequency that was too easily absorbed, you'd get a burnt layer on the outside and it'll stay raw inside.

  • @darkmann12
    @darkmann12 3 ปีที่แล้ว

    The intro is sweet XD :D

  • @MLX1401
    @MLX1401 3 ปีที่แล้ว

    Noisy microwave ovens? You sure aren't talking about my precision Rohde&Schwarz oven.

  • @jhbonarius
    @jhbonarius 3 ปีที่แล้ว

    Loved this! Thanks!

  • @CreaseysWorkshop
    @CreaseysWorkshop 3 ปีที่แล้ว

    Great Fransplaining!

  • @jeromevaneersel8491
    @jeromevaneersel8491 3 ปีที่แล้ว

    Fran i thought that the grid was to cut off the electrons for multiplexing multiple vfd's? Afaik the russian dot vfd's like the IV25 only have cathode and anodes. If you look carefully with a magnifier you'll see a very weak glow, its like 800 degrees for oxide coated cathodes.

    • @FranLab
      @FranLab  3 ปีที่แล้ว

      You can do that (grid switching) but even the multi-digit displays have a single grid in them.

    • @jeromevaneersel8491
      @jeromevaneersel8491 3 ปีที่แล้ว

      @@FranLab interesting. I took apart a pos display that had a grid for each 5x7 field. Maybe these are different. Will check when i get home in two weeks.... now at sea

  • @Ascania
    @Ascania 3 ปีที่แล้ว

    Franlab! Finally again!

  • @hunter00047
    @hunter00047 3 ปีที่แล้ว

    OK fran, is a sphere or circle round, or made of infinite lines. If made of lines then atoms must have a crystalline shell and everything is made of crystals. We do not have the technology to zoom to such a level.
    What are your thoughts? ☢️
    Ps I know a circle only has one side, you may also have to explain this to your subscribers.

  • @WarrenGill
    @WarrenGill 3 ปีที่แล้ว

    Fun!

  • @qawsedyhujik6428
    @qawsedyhujik6428 3 ปีที่แล้ว

    Soviet tube you show at the beginning and call Russian has 0.9 v cathode heating voltage and can work with anodes voltage staring 9v, even less but brightness will be small, max anode voltage is 30v. ИВ-11 tube

  • @НиколайМельников-б3з
    @НиколайМельников-б3з 3 ปีที่แล้ว

    Super tehnolodgi and "CCCP"
    1980...70. Lamp indekeihon
    Big ...!! big .! PRIBORS perspektiw
    taim !!
    Удачи и успехов !!

  • @SamiJumppanen
    @SamiJumppanen 3 ปีที่แล้ว

    Excellent!

  • @zomaardan
    @zomaardan 3 ปีที่แล้ว

    I wish i was smart like you.
    You are awesome.

  • @fredbos5997
    @fredbos5997 3 ปีที่แล้ว +1

    What education did you take to become so technical in electronics??

  • @TheGramophoneGirl
    @TheGramophoneGirl 3 ปีที่แล้ว

    You rock Fran

  • @ProperLogicalDebate
    @ProperLogicalDebate 3 ปีที่แล้ว

    5:53 Don't we all?

  • @ngneer999
    @ngneer999 3 ปีที่แล้ว

    i put my cellphone in a microwave oven (off of course) and I could still call it and see it light up. Why doesn't a microwave oven block cellphones?

    • @FranLab
      @FranLab  3 ปีที่แล้ว +1

      It's not a Faraday cage.

  • @zorvlatch
    @zorvlatch ปีที่แล้ว

    How much rf does your brain radiate?

  • @rbotton6272
    @rbotton6272 3 ปีที่แล้ว

    vacuum flouresecent displays in microwaves ftw

  • @markissboi3583
    @markissboi3583 3 ปีที่แล้ว +1

    Ask Fran bet i dont get a reply . so i wont ask anything
    hardly anyone replies to comments xd
    i wouldnt reply to all comments my typing hand gets very sore in 1/2 hr

  • @VEC7ORlt
    @VEC7ORlt 3 ปีที่แล้ว

    Yay, old intro, got a bit tired of clunk-clunk-clunk one.
    Hah, microwaves aren't even in the same ballpark as infrared, its radio, micro, terahertz waves, then infrared and visible.

  • @walterschwede4189
    @walterschwede4189 3 ปีที่แล้ว

    And do you have any logical explanation for this transition from cloud-like to disk-like? Nummerical simulations show it, nature shows it (spiral galaxies, solar systems). But why? And old galaxies become elliptical, so they go back to a cloud-like shape. Any comprehensible reason for that behavior? Anybody?
    And Fran: Sprich doch öfters mal deutsch! Das machst du gut.

  • @geneallen5758
    @geneallen5758 3 ปีที่แล้ว

    Keeping score here...you speak with your left hand about 75% and your right hand about 25%.