The Vacuum Tube Diode
January 7, 2026 • EPISODE 292
What invention helped spark the age of electronics? In this episode of Science LIVE, Dr. Roger Billings and the Protégés break down the vacuum tube diode—one of the earliest electronic components that made controlling the flow of electrons possible. Learn how this simple device works, why it was so important in early radios and computers, and how it laid the groundwork for modern electronic technology. Join us for a clear, engaging look at a key milestone in the history of electronics.
About DrB
Dr. Roger Billings is a visionary innovator whose work has touched the lives of millions of students and transformed the landscape of education. Widely known as “DrB” to the countless kids who benefit from his groundbreaking Acellus learning system, Dr. Billings has dedicated his life to advancing education through technology.
As part of DrB’s lifelong commitment to supporting education, Science LIVE was launched as a way to “give back” by mentoring students in conjunction with the Roger Billings Scholarship Program.
Read more about DrB »
About the Roger Billings Scholarship Program »
I like David and Kaleb.
did you know that when you “smell the rain” you are actually smelling the chemicals and oils the plants release when they get wet? Always a fact that never ceases to amaze me!! ;3
This science live was fantastic!
Honestly one of the BEST episodes I ever saw what a great way to start the year! Happy new year and I vote for both David & Caleb!!!
I really enjoy learning about radio waves
SCIENCE LIVE IS GREAT
Hi from Canada! This live was amazing! Can’t wait to watch more.
I vote for both Caleb and David. Happy Belated New Year!
Happy New year everyone. Both Caleb and David did a great job.
Can I vote both?
Really exctited for a whole new year of science live! Cant wait to see whats in store for 2026.
Happy new year Dr. R! Love this Science Live episode!
how do the vacuum tubes effect our life today?
Thank you for the Science Live video this week. It was very interesting.
HAPPY NEW YEARS!!!!!
Amazing video! I vote Caleb.
I say both David and & Caleb because they’re a perfect team when working together .
I watched this in Idaho
I think David and Caleb both explained things properly and was super easy to understand!
Happy New Year! 2026 is gonna be a great year!
I voted Caleb
Science is fun
I vote Caleb and David.
happy belated new year!!!!! i vote for david.
I think David and Caleb are both good proteges.
It is really cool how people can make a robot small.
I vote Caleb and Happy New Years Acellus
Thank you Acellus live it was great. I like them both
This was a fun Science Live!
caleb is good
It’s true when you find the right book, you enjoy reading them
Today on Science Live, I learned about the vacuum tube diode and Sir John Franklin. The vacuum tube diode, also known as the Fleming valve, was invented in 1904 and is used to control the flow of electricity. I also learned that Sir John Franklin was a British Royal Navy officer who served in the Napoleonic Wars and the War of 1812.
Never thought I would enjoy learning.
How cool would it be if they started teaching Morse code in schools? Keep rocking, Acellus! This live was great!
I going to vote for Caleb because I love music and I love editing too.
awesome wisdom from the one and only roger billings!
Awesome video! I voted for Caleb!
so cool and i vote for David
GREAT VIDEO! this is like the highlitght of my week y’all. Thank you so much for doing these!
I love my ASL teacher
What is a diode?
I love science. Yes vote for Caleb and David.
I loved this one!
I think both David and Caleb are great candidates!
i love science live! i vote for both guys.
I think David and Caleb both would be awesome!!!!
Happy New Year!! I vote both!!
Happy New Year! I vote for David and Caleb
Thumbs up Caleb Thumbs up David
Yes. David and Caleb for being proteges.
I love Science Live!! Explaining how plants breath and being able to watch them breath is so cool!!!
I can’t wait till next weeks science live!
Science Live is always intresting!!! I love plants so learning that scientist have a way to watch plants breath is so cool.
I learned that there are two main ways that electricity flows: DC means that the electricity is flowing in one way, and AC means that electricity is flowing back and forth. The video was fun.
that video on the vacuum tube diode was really cool
plants breathing is amazing!!!!!!
Vote for both David and Caleb! Very creative and easy to understand. Enjoyed this episode!
Happy New Year from Arkansas!!!
David : )
I love science so much
That was awesome when they built the wave. The part when Area 51 came was funny.
I vote for both David and Caleb!
Caleb and David yes!!
Love these, keep it up and happy new year!
Im excited for all the new things i will learn with Science Live in the new year!
I never knew that plants can breathe, that’s so cool!
I think this is my favorite episode of science live
I thought the dive into something so foundational in electronics was well made and in depth.
Tumbs up David. Thumbs up Caleb
david is my favorite because hes like hunting
One thing I liked about todays video is learning about how Sir John Ambrose Fleming and Thomas Edison got together and had a plan on how they would be able to create the Vacuum Tube Diode.
Great Science Live video to kick off 2026.
I LOVE ACELLUS!!!!
I really like learning and getting to know people.
It was very hard to pick! I voted for both! Happy new years!!
happy new year science live. i vote for David & caleb
This was such a nice video! I loved the section where they talked about AC and DC (although i’m surprised there were no AC/DC jokes). Also I vote for Caleb not only because his name is awesome but also because guitar is awesome
no David-NOT THE DEER, lol the tree sitting XD love that, both videos were funny, I also like when Caleb says (yeah Caleb is definitely the favorite grandson)
Both were good! But I have to go with Caleb!
Will from Georgia
Both are good i had to go with Caleb though
OH MY GOSH THAT ROBOT IS SO SMALL!!! what a great episode 😁 thank you!!
I like the new dudes and I am glad to still see R51 in 2026.
I vote for both I can’t choose just one!
BOTH!!!!!! Happy New Year!!!!! Watching from Massachusetts!
I liked the fact that Caleb and David broke down the terms in the sentence before they made us think about the question.
Honestly, I’d vote for both Caleb and David. It would be too hard to choose just one!
I never knew plants could actually “breathe” I always thought they could survive just off being watered.
Both Caleb and David are my votes!
Caleb said he loves music and does video editing witch made me smile because I actually love music as well and play several different instruments including Guitar. I’ve played Guitar for a couple years now, so I vote for Caleb.
I vote for both Caleb and David. I like how they have very different personalities but also work together very well. I love how they explain things.
Here from Missouri. I am almost finished with all my classes for graduation and a little sad that I will not know what to do without having these classes every week. I am off to technology college after graduation and thanks to Accellus, I know I will be successful. I will be on my way to become a electrician. Nervous and excited all at the same time.
yes Caleb yes David. Hope you had a Amazing New Year!
Happy New Year, science Live!!!
I vote for both David and Caleb. I really liked the presentation
I loved the segment about Samuel Morse!
Thanks for such a wonderful topic, vacuum tube Diode. I vote for David.
Wow I didn’t know plants breathe.
I’m so happy that SCIENCE LIVE IS Back!
i vote for both Caleb and David
Happy Belated New Year Science Live! I vote for both David & Caleb!
David and Caleb did so good. We really enjoyed seeing them and learning from them. It was so funny when Area-51 appeared at the end.
I knew plants took in carbon, but I didn’t know they breathed it.
I love how it shows you to never give up.
I definitely vote yes for David and Caleb! Have a good New Year, everyone!
This live was amazing!
Anastasia is so amazing that she can make a new way to find out if tornados are forming.
I love these videos
plants breathe? crazy!
They were both great but I vote Caleb.
Yeah! That is how they survive. If they had no air they would not be able to live.
It’s so cool that plants breathe!
Science live is so fun to watch I cant wait for next week to watch another one.
how small can the robots get
Such a hard decision between David and Caleb. Can we vote for both lol? This may have been the best science live yet! Happy New Year everyone.
I love science live.
Happy New Year!!
The writing program looks fun! I vote for both Caleb and David.
It’s hard to choose. David-yes, but Caleb…also yes 👍! Anyway, HAPPY NEW YEAR🎊!
How do you program the worlds smallest robot to swim?
its programed while its made.
This is the best one yet!!!!!!!!!!!!!!!!!!!!!
yes I agree!
Happy new year!
Watched from Alabama.
Hey wait a minute, I was raised in Alabama!
Happy New year!
I love science live!!!!
Both are very good! Had to go with David though haha!
David and Caleb are funny
Pick both!
I like how he talks about Morse’s code was being made and the process of what inspired him.
David and Caleb are both good candidates.
Happy New year from Seymour, Tennessee
Why does the little robots need light?
I like both of them. They make a great team! I really like how they explain and show it.
I vote for both. And happy new year!!!! 🎊🎊🎊
Caleb
This is cool!
Comment
I am really happy both David and Caleb will be teaching us more in the future. They are really funny.
That was really good!!! I enjoyed the class.
Science is awesome!
I liked David and Kaleb’s video a lot. They have to make more like that!
I love acellus
amazing stuff like always!!!!!
I love playing basketball!
Happy New Year ! who was the first person to invent the vacuum tube and what year was that?
is AP literature a new class? If so, I would love to take it and love David. And science live. And happy new year 🙂
son and grandson, R51 is so funny
Happy new year everyone! Have a great 2026!
How do the little robots swim?
Yes Kaleb yes David
Science live is the best!
That’s so cool she used drones to help people stay safe during tornados.
I think David and Caleb should be working together as a protégé team!
If its not to late to vote, I vote for David. 🙂
I enjoyed watching this. Happy New Year!
I really like watching Science Live.
I liked the part where the origin of telagraph was explained. also, happy new year!
I like both!
I enjoyed the video today!
Wait a minite there is a town in Montana named billings is it named after you?
HAPPY NEW YEAR!!!!
This is my first science live and love it.☺️
I love science live!!!!!!!!!!!! Happy new year!!!!!!!!!!!!!!!!!!!!!!!
I LOVE THE LIVES SO MUCH SO THANK YOU.
Cannot believe how small those robot chips are! and able to swim haha. Happy New Year!
The Vacuum Diode and seeing how the waves of electricity work was very interesting.
not David or Caleb i think it should be R51
Science is so cool!
Hello from Maryland. Happy New Years to all. I love to get lost in a book, too!!
Happy new year!
And I like both but I favour Caleb
BOTH!!! AND HAPPY NEW YEAR!!!!
The 30 second montage was really funny. they’re both really good but I like David better.
Science is so amazing!
Happy New Year to everybody!
First science live of 2026!! Happy new year everyone!
Happy New Year! So glad to have Science Live back
In a half-wave rectifier circuit using a vacuum diode, what is the state of the diode during the negative half-cycle of the AC input?
In a vacuum diode, why does current only flow from the cathode to the anode and not in the reverse direction?
Both of them! Thanks!
Caleb was great, but I prefer David for sure, MORSE CODE IS SO COOL!!!!! Happy New Year!
It is cool I agree with you
Why did Dr. Roger billings create Acellus.
Because he wants to help us learn.
R-51 is so funny 😂
Dr. John mentioned that every robot has its own personal ID. What if the ID’s are mixed up? Would the robots still work?
Happy New Year to everybody!
YAASSS, Acellus is NUMBER 1 on my favorite school program list. Reply if you love Acellus, if you don’t, it’s okay, I’m not pushing. BUT PLEASE!!!!!
I loved this episode. It was fun learning about the tiny computers and seeing Dr billings son and grandson give a lesson as well.
I love science live!
I love dr John!
Both!!
loved learning today!
I think science live was funny and inspiring I also think that both of them should get picked
and I’m so excited to continue with Acellus
I like both but i like Caleb more!
Great stuff as always!