chemical rectifier/liquid diode

[coppercone2]

https://www.rfcafe.com/references/popular-electronics/experiments-chemical-rectifier-popular-electronics-january-1965.htm

I thought that that was interesting. Any old timers work with one?

[MarkS]

That would a fun and easy science experiment!

[coppercone2]

I am curious about their use in labs etc, the article alludes to them being taken seriously at one point.

[MarkS]

I am curious about their use in labs etc, the article alludes to them being taken seriously at one point.

I'm curious myself. Apart from the standard silicon diode rectifier, all I know of is the mercury arc design.

[coppercone2]

the interesting part is that they can go way back in terms of people being to make them. I wonder if it would rectify HV discharges from a spark, i.e. imagine some egyptians or maybe more realistically Alexandria era helenic greeks making a inefficient battery charger that ran on rabbit fur and a steam engine or something

[DavidKo]

Only chemical rectifier I'm aware of are mercury rectifiers - used in high voltage/high current applications like DC trains power stations (3kV DC).

[Andrew_Debbie]

A pair of mercury arc recifiers were in use at the Royal Opera House in Covent Garden.    Until 1977(!), they had been used to power the stage lifts, driven by German U-boat engines obtained in reparation after WW1.

They are now at a working museaum.

https://kemptonsteam.org/collection/mercury-arc-rectifiers/

[PA0PBZ]

Something doesn't add up here. After forming the author measured 50K forward resistance for the rectifier, yet with 16V ac input and a 2K5 parallel resistor he measures 14V across that resistor  So does the forward resistance vary with the voltage or current or what? Borax anyone?

[jonpaul]

in 1900...1930s before solid state and selineum, was the mercury arc rectifiers and Tungar lamps.

Often for lead acid battery charge.

the DIY hobbyists had various electrolytic rectifiers, a carbipon rod and aluminum plates in a jar of liquid electrolyte, Low voltage, poor efficiency, but they did work.

Jon

[Alex Eisenhut]

Could this be the serious device you are thinking of?

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

Read this for more fun history

http://www-smirc.stanford.edu/papers/chapter1.pdf

[joeqsmith]

I tried something similar using copper oxide to form the junction.  Fun experiments. 

[TimFox]

As described in https://en.wikipedia.org/wiki/Electrolytic_detector (mentioned by Alex Eisenhut above), R A Fessenden invented his electrolytic detector in 1903.
His device inserted a fine noble-metal wire (usually platinum) into a strong acid (sulfuric or nitric), and the two-terminal device was biased by a small DC voltage from a potentiometer (original meaning).
A later version had the wire and acid sealed inside a glass tube.
I believe that this was the first practical detector capable of use with AM (also pioneered by R A Fessenden), and preceded the point-contact galena crystal detector.
Probably the worst invention by Marconi was the "coherer", that was used in wireless before the electrolytic detector, crystal diode, and Audion were developed.
Fessenden surprised many wireless operators in 1906 when he broadcast himself playing the violin by AM (using a high-frequency alternator and telephone carbon microphone).
There is some historical controversy about that event, which preceded Lee de Forest's broadcasts in 1907.