Author Topic: Oscillator Valves Etc. Triggering ???  (Read 219 times)

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Online GlennSprigg

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Oscillator Valves Etc. Triggering ???
« on: April 06, 2020, 02:03:29 pm »
I don't know WHY I keep punishing my 'brain' when my time is limited?? Sigh...
It seems to just 'snowball' when reviewing certain topics, and I can't stop!!...  :P

Yet another "Mr Carlson's Lab" equipment test, where half way through, he was talking about a previous post, about certain pieces of equipment that had a simple Light-Globe hidden under the Chassis in close proximity to certain Valves. I'm sure experts here will know, but it is to do with exciting the circuit, to result in controlled oscillation. Some devices/parts/components utilized RadioActive internal additions for this purpose, but having a half-life of about 5 years, this would have rendered such valves etc useless now. So adding a physical light-source adjacent to it, would result in the continued usefulness of such a circuit today...

THIS video is/was about 'firing-up' an old X/Y scope device. However, look at 16:21 to 22:15 to see what I am talking about...



Although fascinating, & beyond what I ever learnt before, I need to scale back the 'snowball' effect !  :)
I don't even know why I'm totally rebuilding my workbench, & power-supplies etc. I think I just don't want to loose the part of my 'mind' that used to give me so much joy. It's like if I lose that then I have nothing left?  I'm now just 're-inventing' old simple resonant circuits and playing with oddball components to keep my 'brain' active, and pass on what I know to certain friends/family...
 

Offline vk6zgo

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Re: Oscillator Valves Etc. Triggering ???
« Reply #1 on: April 07, 2020, 12:58:11 am »
Interesting!
Funny thing is, I've never run into the practice over many years in the business.
Mostly, if gas tubes played up,you just replaced them, & apart from regulators & the odd Thyratron from time to time, they weren't a big part of my experience.

Most equipment after the early '50s employed "hard timebases", using normal vacuum tubes.
I have certainly seen equipment with incandescent lamps inside, but they were mostly to control the feedback on Wien bridge oscillators, so as to stabilise the output level.

Here are some other "funnies":-

(1)How did the flashcubes that didn't use a battery supply work? (I do know this one, it is on line)

(2)Here is the really weird one!

Many years ago, at my work, we had made up a bunch of small Mains distribution panels which were to be fitted at the base of equipment racks.

Someone realised that 120v neon indicators (in rectangular plastic mouldings), had been fitted by mistake.
We were told to remove them, destroy them & replace them with 240v ones, so a bunch of us  sat there, removing them.

Somebody suggested a good way to destroy them would be to fling them at the concrete floor.

On doing this, we discovered that on impact, the neons would briefly flash, so we had a lot of harmless fun
making this happen.
The impact definitely destroyed them, as trying again with one that had already hit the floor produced no flash.
 
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Online GlennSprigg

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Re: Oscillator Valves Etc. Triggering ???
« Reply #2 on: April 10, 2020, 12:20:02 pm »
Interesting!
Funny thing is, I've never run into the practice over many years in the business.
Mostly, if gas tubes played up,you just replaced them, & apart from regulators & the odd Thyratron from time to time, they weren't a big part of my experience.

Most equipment after the early '50s employed "hard timebases", using normal vacuum tubes.
I have certainly seen equipment with incandescent lamps inside, but they were mostly to control the feedback on Wien bridge oscillators, so as to stabilise the output level.

Here are some other "funnies":-

(1)How did the flashcubes that didn't use a battery supply work? (I do know this one, it is on line)

(2)Here is the really weird one!

Many years ago, at my work, we had made up a bunch of small Mains distribution panels which were to be fitted at the base of equipment racks.

Someone realised that 120v neon indicators (in rectangular plastic mouldings), had been fitted by mistake.
We were told to remove them, destroy them & replace them with 240v ones, so a bunch of us  sat there, removing them.

Somebody suggested a good way to destroy them would be to fling them at the concrete floor.

On doing this, we discovered that on impact, the neons would briefly flash, so we had a lot of harmless fun
making this happen.
The impact definitely destroyed them, as trying again with one that had already hit the floor produced no flash.

Wow... vk6zgo... you really helped my scaling back the 'snowball' effect of my desire to learn!!   :-DD
I found the following, about old FlashCubes/MagiCubes...
https://www.lightstalking.com/flashcubes/
The 'younguns' here probably have never even seen or heard of them!  :)
RE: the Neons... I've not looked it up, but I would 'imagine' the shattering Glass might create a high voltage, something like the hammer on a crystal inside a cigarette lighter or stove-top lighter??  Seems feasible to my slowly retarding brain!!   8)
 

Offline Cyberdragon

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Re: Oscillator Valves Etc. Triggering ???
« Reply #3 on: April 10, 2020, 03:20:06 pm »
I've seen a NIB flashcube camera in a antique store once with all the original bulbs and spare cubes in boxes thrown into the case (IDK if there was extra film too, but it looked as if someone bought a camera and supplies back in the day then forgot about it).
*BZZZZZZAAAAAP*
Voltamort strikes again!
Explodingus - someone who frequently causes accidental explosions
 
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