Thank you! This took me back over 40 years - I remember having very similar equipment in the school physics lab. There was an electron deflection tube which fitted in the same frame, the beam of which could be controlled using helmholz coils. Luckily one of the physics teachers was also a games instructor and a friend and I were often able to scive off games to do physics experiments. The only stipulation being that we left the lab tidy! No supervision at all but I suppose we must have been as trustworthy as we appeared 😂. Happy days and as a radio amateur I still love valves.
Excellent! Yes, these Teltron tubes were in a lot of schools and my fear is people will forget how to use them or be frightened off by working with HT and EHT supplies (even though they have huge series internal resistances). Have you seen my other videos on these? Here, for example, is the electron diffraction one. th-cam.com/video/CR2frJzQZ8k/w-d-xo.html and here is the deflection one with the Helmholtz coils th-cam.com/video/7hJxn4l47X8/w-d-xo.html
I like to demonstrate the space charge first: anode-cathode pd with heater pd. I have just tried it with an EY86 EHT diode valve and an AVO 8, which show the effect perfectly. I also do it in a vacuum chamber, with a magnet on a feedthrough manipulator to demonstrate deflection of the charges - although this is better with my home-made deflection tube in the chamber.
Thanks. yes that is a great idea. The EY86 is an interesting 'tube' in its own right with Mullards not normally bothering with any getter at all. For classes I lke the scale and size of the Teltrons. We did have a vacuum pump top mounted stage for demonstrating such things in an evacuated bell jar but it was all pretty unstable and many of the bits had gone missing but you were meant to build up valve electrodes bit by bit inside it to demonstrate to students diode, triodes and the like. Bet no school does that now! Thanks again for watching and taking the time to share your experiences. I need to do more with the Teltrons especially the triode one.
Given there are two things you can vary here - the filament voltage and the plate voltage - it might make a nice project to show how the resulting current depends on both voltages using a heatmap, contour or 3D plot. It would reveal the saturation effect over a range of voltages, and any current threshold phenomena.
Funny you say that, as I am just working on a vacuum fluorescent display video and they make it really clear that small variations in filament voltage have a huge effect on brightness, less so than segment anode voltage. Thanks for the great suggestion!
Thank you! This took me back over 40 years - I remember having very similar equipment in the school physics lab. There was an electron deflection tube which fitted in the same frame, the beam of which could be controlled using helmholz coils. Luckily one of the physics teachers was also a games instructor and a friend and I were often able to scive off games to do physics experiments. The only stipulation being that we left the lab tidy! No supervision at all but I suppose we must have been as trustworthy as we appeared 😂. Happy days and as a radio amateur I still love valves.
Excellent! Yes, these Teltron tubes were in a lot of schools and my fear is people will forget how to use them or be frightened off by working with HT and EHT supplies (even though they have huge series internal resistances). Have you seen my other videos on these? Here, for example, is the electron diffraction one. th-cam.com/video/CR2frJzQZ8k/w-d-xo.html and here is the deflection one with the Helmholtz coils th-cam.com/video/7hJxn4l47X8/w-d-xo.html
I really like ur lessons
Thanks, that's kind of you. I do hope your studies are going well. Plenty more lessons to come!
Yh ..buh I wish u go through some electromagnetism
@@ssenyangesimon123 I think I have done some bits but may not have published them yet. Any bits of e-mag particularly?
I like to demonstrate the space charge first: anode-cathode pd with heater pd. I have just tried it with an EY86 EHT diode valve and an AVO 8, which show the effect perfectly.
I also do it in a vacuum chamber, with a magnet on a feedthrough manipulator to demonstrate deflection of the charges - although this is better with my home-made deflection tube in the chamber.
Thanks. yes that is a great idea. The EY86 is an interesting 'tube' in its own right with Mullards not normally bothering with any getter at all. For classes I lke the scale and size of the Teltrons. We did have a vacuum pump top mounted stage for demonstrating such things in an evacuated bell jar but it was all pretty unstable and many of the bits had gone missing but you were meant to build up valve electrodes bit by bit inside it to demonstrate to students diode, triodes and the like. Bet no school does that now! Thanks again for watching and taking the time to share your experiences. I need to do more with the Teltrons especially the triode one.
Brilliant. Thank you!
Excellent! Glad you liked it and thanks for taking the time to watch and comment!
That must have been a lightbulb moment for Edison. (Sorry, couldn’t resist! 😊)
Indeed! In seriousness, I wonder who initially coined the phrase as it cannot be that old therefore.
Given there are two things you can vary here - the filament voltage and the plate voltage - it might make a nice project to show how the resulting current depends on both voltages using a heatmap, contour or 3D plot. It would reveal the saturation effect over a range of voltages, and any current threshold phenomena.
Funny you say that, as I am just working on a vacuum fluorescent display video and they make it really clear that small variations in filament voltage have a huge effect on brightness, less so than segment anode voltage. Thanks for the great suggestion!