Liquid diodes!

[DavidAlfa]

I never heard about this, I'll save some lead for emergencies!

[Infraviolet]

There was another type of liquid diode too, used mercury held at a temperature where it was on the verge of evaporating. Its ability to rectify, and this was for distribution and railway level AC, not low voltages or 240V, depended on some sort of asymmetry in the direction that mercury gas and liquid droplets would move under applied voltages, might have been related to ionisation of them.

[DavidAlfa]

Yeah I know mercury arc rectifiers 

[Stray Electron]

Yeah I know mercury arc rectifiers 

   The early ones used large, open pools of mercury!  I have pictures around here somewhere.

[amyk]

I remember reading about something similar in an old book of electricity, but it was using a copper sulphate(?) solution. I can't seem to find that book at the moment but I did find this:

On the Theory of the Electrolytic Rectifier (1902): https://ia800708.us.archive.org/view_archive.php?archive=/22/items/crossref-pre-1909-scholarly-works/10.1103%252Fphysrevseriesi.10.116.zip&file=10.1103%252Fphysrevseriesi.15.327.pdf

[TimFox]

The pioneer R A Fessenden built electrolytic detectors (diodes) with a wire in a liquid bath.
He is credited with the first AM broadcast, and a diode detector was necessary (a coherer would be useless on AM).
https://en.wikipedia.org/wiki/Electrolytic_detector

[AVGresponding]

Yeah I know mercury arc rectifiers 

   The early ones used large, open pools of mercury!  I have pictures around here somewhere.

Photonicinduction has a couple of vids:

[DavidAlfa]

   The early ones used large, open pools of mercury!  I have pictures around here somewhere.

It would be such a mess! Where did all the evaporated mercury condense?
Not to mention the terrible health consequences if exposed to the vapours.

[tom66]

Flames can also be used to rectify current.  This is used to effect in most modern home gas boilers to detect the presence of the flame, since carbonisation would create a parallel path, but only the flame creates a conductive path that works in one direction.  I believe low voltage AC is passed through the rectifier and a detection circuit (or more likely a microcontroller nowadays) is used to isolate the gas supply if ignition fails.

[coppice]

Yeah I know mercury arc rectifiers 

   The early ones used large, open pools of mercury!  I have pictures around here somewhere.

I've never seen an open one, and I don't know how that would work. All that oxygen is going to cause trouble. I believe they are usually filled with an inert gas, rather than evacuated, because the glass envelopes are not that thick.

[DavidAlfa]

Flames can also be used to rectify current.

I knew flames conducted electricity, but not they rectified it!

[amyk]

Flames can also be used to rectify current.

I knew flames conducted electricity, but not they rectified it!

I'm not very familiar with the physics, but I suspect the effect is similar to a vacuum diode.

[BrokenYugo]

Flames can also be used to rectify current.

I knew flames conducted electricity, but not they rectified it!

You can apparently even insert a grid and make a triode, interesting stuff. There are some vids on YouTube from a few different people if you look around.

Some good reading here. http://www.sparkbangbuzz.com/flame-amp/flameamp.htm

[coppice]

Flames can also be used to rectify current.

I knew flames conducted electricity, but not they rectified it!

I'm not very familiar with the physics, but I suspect the effect is similar to a vacuum diode.

Yeah. A vacuum diode makes a cloud of electrons. A flame makes a cloud of ions. They are all charged particles, which will only drift in a particular direction in an electric field. As someone else said, you can use a grid to make a triode from a flame. You can also put plates around the flame and wiggle the ions with an audio signal, making a loudspeaker.

[SiliconWizard]

In the end it's just polarized dark fluid.

[Alex Eisenhut]

Uh oh, it's that time of year I post this link
http://www-smirc.stanford.edu/papers/chapter1.pdf

[Dacian]

I recognize that face in the video. Free energy and perpetuum mobile type stuff.
Not sure why anyone will watch that channel.

[DavidAlfa]

You're very wrong!
He makes a lot of videos of rare mechanisms and engineering stuff, not that kind of BS.