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Old 01-26-2014, 11:22 PM   #31
MattBaker
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Additionally russian electricity prices...probably cheaper than 90% of everyone else's.
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Old 01-26-2014, 11:25 PM   #32
N_Molson
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/me still thinks Artlav lives in a RBMK nuclear powerplant...
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Old 01-26-2014, 11:30 PM   #33
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Quote:
Originally Posted by Artlav View Post
 The usual.
Power does not necessarily equal total energy consumed.

You can have a megawatt pulse laser that is only consuming 1 milliwatt*hour of energy per hour.
What matters is how long the thing is on, which the big stuff is rarely long.
Still, a Megawatt pulse laser should approximately consume one kWh of power. , which means, you should not fire it too often, about 1000 times and you would have doubled my power bill.
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Old 01-26-2014, 11:44 PM   #34
Andy44
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Quote:
Originally Posted by Urwumpe View Post
 Still, a Megawatt pulse laser should approximately consume one kWh of power. , which means, you should not fire it too often, about 1000 times and you would have doubled my power bill.
If you have a megawatt laser, people give you your power for free, or else.

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Old 01-27-2014, 07:26 AM   #35
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Originally Posted by Urwumpe View Post
 you should not fire it too often, about 1000 times and you would have doubled my power bill.
I think I'd run out of targets way before that...
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Old 01-27-2014, 08:48 AM   #36
4throck
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Another one of my favourite retro tech is mechanical TV:

https://en.wikipedia.org/wiki/Mechanical_television


Here's Mr. Baird setting up his "televisor":


And here's the type of image it delivered:


The interesting thing is that the bandwidth used was low enough for transmission over a regular AM channel. So in was perfectly within the available "consumer" tech of the time.

An interesting side product of this mechanical scanning tech is of course the Fax machine. That was used for the Luna 3 images... and that's a subject for another post :-)
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Old 01-27-2014, 09:34 AM   #37
MaverickSawyer
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Quote:
Originally Posted by Artlav View Post
 Nice...
You know, thinking about it in comparison made me realize that i was just slacking off calling it difficult with such a huge valve and it's big clearances.

Here, let me try again with proper setup.

Heater on, power off:
{image}

Power on, heater on:
{image}

And with heater off, as it cools down:
{image}
{image}

With it at almost cut-off cold the plasma turns completely red.
I wonder why that is?
{image}

Be aware that this is only roughly 0.0001% of power it's rated for.
I tried discharging some HV capacitors with it as a switch, and that produce a brilliant blue flash that is truly impossible to get on camera.

AFAIK, these cans are of standard size everywhere, so it's still a valid reference.

High voltage only.
EM energy is proportional to voltage difference between the cathode and the place the electrons hit.

For regular 200-400V valves the emissions would be only 200-400eV - harmless, can't penetrate even the regular air.

Things get interesting with tens of KV - an old tube TV CRT stabilisation triode like 6S20S is rated at 25KV, and it emits enough soft X-rays even with glass around it that it was shielded and eventually replaced with different technique.

My modulation tube can also quite possibly produce a fair bit of X-rays if I put full 33KV across it.

But the real deal starts from 45KV and up, where there are usually only special tubes.

Defectoscopic X-ray tubes have beryllium window that allow soft X-ray out (glass still absorb most of them at this level), and soft X-rays are absorbed by tissues quite well (heat-wise, not ionizing-wise), so trying to get a shot of your hand from one can easily cost you a hand.

Medical X-rays are 100KV range, and they are hard X-rays that go through glass, tissues, etc easily - these are less directly harmful than soft ones (no heat, all ionizing), but they shine through anything, so you need actual shielding.

These are really nice too.
Pity mercury is so stupidly toxic.

No wonder. Tubes are hard to kill by EMP or radiation.

---------- Post added at 23:56 ---------- Previous post was at 23:35 ----------

Here is the glow in 1920x1080, if anyone want a wallpaper
{image}
I am going to have to introduce you to my dad. He worked on vacuum tubes for 17 years. He would probably get a real kick out of seeing these...
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Old 01-28-2014, 12:46 AM   #38
Izack
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Seriously awesome pictures and videos, Artlav and Andy44. Really sparks an interest in old analogue electronics.
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Old 01-28-2014, 05:45 AM   #39
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Speaking of old computers, Jöhan Jöhannsson is a musician whose dad worked on an IBM 1401 computer back when his government first bought one, so he composed a piece of music that uses a 1401 as one of the instruments. It's that synth sound in the beginning of this. It's so beautiful, it's almost like the computer is crying. I saw this guy live once in Philadelphia and am a huge fan.

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Old 02-01-2014, 09:17 PM   #40
Artlav
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Quote:
Originally Posted by Izack View Post
 Really sparks an interest in old analogue electronics.
Yeah, they are surprisingly interesting.
Being largely obsolete, vacuum tubes can, however, let you do things that you just can't do the same way with modern components.

Take a plasma speaker, for example - a high voltage arc that makes sound.
These are typically relatively complex, you drive a flyback transformer with PWM to get an approximation of the sound - an IC or two, several transistors, the modulation and the HV production clumped into a single block.

With a valve, it's dead simple - one tube, one transistor to drive the grid, an HV source and a music player.



Because a suitably high voltage tube can modulate tens of kilovolts all by itself.
There are basically no transistors or other semiconductors in open sale that can do the same thing, and whatever speciality things were made are likely worth a whopping lot.

But a valve that can do this is under $5 new old stock.



They are, however, really tricky to tune, so the sound quality tend to be worse.
There are both cracking from excessively primitive driver, and the classic tube amplifier distortions (that people pay big money to hear, for some reason).



So, it's nice to know how this old technology work.
There is always a chance that a good idea in the future is just a good idea lost to the past.

---------- Post added at 00:03 ---------- Previous post was at 00:00 ----------

Quote:
Originally Posted by Urwumpe View Post
 Still, a Megawatt pulse laser should approximately consume one kWh of power. , which means, you should not fire it too often, about 1000 times and you would have doubled my power bill.
Nah.
A dead simple TEA nitrogen laser produce pulses in the megawatt range.
But they only last for nanoseconds.
So, average power is just a few milliwatts - like a regular laser pointer.

---------- Post added at 01:17 ---------- Previous post was at 00:03 ----------

P.S.
If the picture above don't look simple, here are all the relevant parts after i cleaned the rest up.
Much simpler looking, and even sounds better now.
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Old 02-02-2014, 05:15 AM   #41
Andy44
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Quote:
Originally Posted by Artlav View Post
 Take a plasma speaker, for example - a high voltage arc that makes sound.
Is that similar to using a Tesla Coil as a speaker?

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Old 02-02-2014, 06:48 AM   #42
Artlav
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Quote:
Originally Posted by Andy44 View Post
 Is that similar to using a Tesla Coil as a speaker?
Not exactly.

When you modulate a tesla coil, it's a bang modulation - the amount of bangs per second determines your sound tone.
This way you're limited to MIDI music at best - specific tones.

With a plasma speaker, the current in the arc is sound modulated - more current, it heats up and/or expands, less current - it cools down and/or contracts.
This way you have a continuous reproduction of the input signal in a sound wave.

Finesses vs power, basically.
One is rough, impressive and loud, other is high fidelity, quiet and boring.
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Old 02-07-2014, 02:44 AM   #43
Andy44
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This is an amazing piece of retro-tech from the company that built the Space Shuttle!



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Old 02-16-2014, 05:09 PM   #44
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And now you can emulate the way this stuff was calculated:
http://homepages.slingshot.co.nz/~timb3000/index.html



This virtual slide rule is amazing!!!
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Old 02-16-2014, 06:01 PM   #45
Andy44
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Quote:
Originally Posted by C3PO View Post
 And now you can emulate the way this stuff was calculated:
http://homepages.slingshot.co.nz/~timb3000/index.html



This virtual slide rule is amazing!!!
I have a virtual slide rule app for my smartphone. Useful...for learning how to use a slide rule.
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