Back in the mid-80's, I helped an older electronics guru and ham radio operator build a high voltage (3kV) power supply from surplus parts that included a pair of mercury vapor rectifiers. He wouldn't let anyone walk behind the supply while it was operating. It had an open back and his concerns were the UV light and his fear the whole thing would just explode due to the unknown provenance and condition of the parts. Luckily, nothing ever blew up or caught fire, and nobody got electrocuted. The fellow was nearly blind, and he blamed it on his constant playing with those rectifiers since his childhood.

When I used to operate carbon arc film projectors, they were powered by rather large mercury rectifier tubes (many times the size of the two in the video). We were told to keep the rectifier cabinet door closed when they were operating because of the UV light emitted by them.

I've worked as an industrial electrician, motion controls, 3ph 480, some light rail DC substation rebuilds, some electric arc furnace work at steel foundries, etc. NEVER saw a mercury rectifier until I played Sniper Elite 4. They mesmerized me! I googled them. A video here on KZfaq appeared. Photonicinduction was the channel. Well THAT took a turn! So cool to see here a smaller version! Thanks for this!

Note the steep rise at the beginning, where the voltage is not enough on each sine wave to turn the tube on, but it jumps to a higher voltage as soon as there is enough voltage.

Just a reminder, 113VAC (RMS) would be close to 160V peak.

These old tubes are a strong reflection of the creative genius that created these devices !!

Those are very cool colours! Lovely blue and purple. Amazing that the colour is a total side effect of the rectifiers doing their actual job.

Once upon a time, way way back when, I observed a thyratron in operation. It was part of a DC motor control circuit. It was a phase control circuit, just a bit before semiconductor thyristors or SCRs took over the phase control applications. I mean, there were already small SCRs available, but engineers did not yet know how to really use them. So thyratrons were used as old "familiar and sure working" components. The maximum current was quite limited, but sufficient to drive saturable core amplifiers or "mag-amps". If you find some thyratrons, I believe that would be a nice addition. By the way, a really high current mercury rectifier was called Ignitron and was used in electrochemical applications like galvanic plating. I have never seen one, only read about them in an old book. Another 'by-the-way' item I have used was a short arc lamp in a multi channel oscillograph. The tiny and very bright light could be steered with tiny swinging mirrors onto photo sensitive paper to produce a permanent recording of something before the digital storage oscilloscopes or where Polaroid scope cameras offered too short a snapshot.

I still have an old 60s Telerad Vacuum tube radio somewhere that my Dad bought with his first salary!

Either your camera or your post-production did a good job filtering out the UV emissions that frequently cause MV rectifiers to appear purple on camera. Such a beautiful, ethereal glow.

Great video. Despite dabbling in electronics for the past few years some of the terms and concepts still get confusing. Even though you are using an old tube as an example this is one of the best explanations for a rectifier that I have seen

Ever since I first saw Mercury Arc Rectifiers on PhotonicInduction's channel I have always been fascinated with these components and their construction! Can't wait to watch this too👍

it reminded me of some college work I did many years ago we were experimenting with DC machines. The DC rectifier was a mercury vapour tube about 3 foot tall! That was cool. Although that term hadn't been invented. remember the mercury tube does throw off UV light.

This reminds me of the teletype power supply CuriousMarc was working on :) Lovely glow! Thing of beauty, joy for ever, and you've got lots of the other Dave's enthusiasm. And niiiiiiice Tektronix transformer there. Just don't let the usagi-chan tip the tube off and break it, please... I'll have to do some experiments with thyratrons - got two of them somewhere in my lab.

Theres a real neat video of some folks restoring a teletype machine, i think its either from the 20s or 30s. But the power sypply for this with all of its original caps, still worked and produced super clean DC output.

I'm delighted to see this subject on your channel. I remember one time searching online about Tungar rectifiers because I wanted to get myself one... and I found my video I'd made about my own 1910s Tungar charger which I had forgotten I had recorded and also forgotten I even owned. The curse of having too many videos over too many years. hahaha

After second consideration I will start working with tubes. Nostalgia level off the charts here.

A good youtuber

I remember seeing these old power tubes laying around back in the ‘60s. They were no longer needed. Sad. Thanks for bringing them back to life.

Beautiful LEDs :D

In the 70s there was a rectifier station on my neighborhood. The sign said it was mercury rectifier station for the electric buses (in Brazil they were like trams with a pantograph at the top to the electric line but without tracks). My father worked with mercury rectifiers on radio transmitters: they were HUGE, usually the heating cycle was manual, controlled by push buttons to heat and activate.

I was on an army mountaintop radio site in 1969. We had about a dozen tube based (TRC-24 and TRC 29) microwave sets up there and these had mercury rectifiers in the base of the racks to supply the DC voltage to the system. We were on top of a 3500 ft peak so we did not have a lot of bugs up there but in the spring we had an invasoin of Miller moths that went ape over any UV light source like the mercury vapor security lights around the site. You could see clouds of them around these lights, we were careful to use only dim bulbs above the entry doos to the Quonset huts to not draw any moths to the buildings and that pretty much kept them at bay, However the moths could see that loverly UV glow in the base of our transmitter racks through the windows and they wanted inside NOW. A few would always find a way in and go after the florescent lights and those glowing rectifier tubes. Nothing like a big juicy moth colliding with a very hot tube to ruin your night. They would dive bomb the rectifiers and as soon as the hit that hot glowing glass they would be cooked and could crack the glass envelope of the tube and take a set down till we could get a new tube in there. We ended up lining the metal grills that covered the ventilation holes with copper screening to keep the buggers out.

Oddly enough the colour of the first is very reminiscent of a mercury vapour arc lamp. (especially after it warms up) Very pretty!

this is great, glad to have discovered your channel! Great explanation at the beginning.

Enjoyed this look at rectifier tubes. I never know what to expect from your channel but it's always interesting!

Thank you for the glowing rectifier demo! Love that violet plasma!! If you have a "magic eye" tube in your collection, that could be a good video idea for the near future 👁️‍🗨️

Old vaccuum tubes are so cool to me, i love them.

A very lovely glow!

I love the gleeful personality of you and your channel. I didn't understand it at first but I dig it. I'd love to see some of the biggest tubes in your collection with power applied. I've seen many big ones, but never in an active state.

Loved this - and the heatsink for the dropper resistor for the filament supply made my day! It's perhaps worth noting that Xenon tubes to not have a "right way up" whereas Mercury Vapour tubes must be mounted vertically (as yours) so that any mercury condensate collects away from the anode when the tube is not in use.

I love these tubes. I’m always amazed at the huge mercury arc rectifiers used in the old power stations and the ones in the old underground railway stations for the lifts etc. amazing stuff 👍

Absolutely fascinating! Plasma!! Wow, so cool!! 🤩

Beautiful. I didn't know mercury vapor rectifiers came in such a small package.

Very cool! My grandfather had a battery charger for old cars that had a mercury rectifier. A couple of taps on a transformer, the rectifier and a big old rheostat. Used it in his car repair business back in the days of early cars. Could always tell when it was on by the glow from the tube. :)

I love the old VT127A and the 327A. They both have the uranium glass pin pass throughs! Great video.

I'm going to nitpick a little here at the use of the phrase "boil off" to describe the emission of electrons from the cathode. I would call it charged particle emission, since it requires a strong electric field at the surface to pull the electrons out. Also, the "shield" around the cathode is known as a "Wehnelt cylinder". It helps to keep the electric field lines parallel in order to emit an electron beam that doesn't spread out too much and therefore allows the tube to sustain higher currents by counteracting the repulsive force that the electrons exert on one another. As always, thank you for another fantastic video.

Looking forward to more videos on particular or unusual tubes.

Tremendous video, keep it up champ!!

I liked these when Curious Marc was working on the TTY... Thanks for the deeper dive.... a nice eerie glow is what I think we all look for in vacuum tubes.... I had an old tape recorder when I was a kid and the tube VU meter was mesmerising.

Great video! Excellent camera work!

They look amazing.

I remember being little and my friends dad used to have equipment that used these , it looked amazing in the dark . Very informative I always wondered how these worked. Thank you very much

Always fun to do !...cheers.

that was a trip down memory lane. very nostalgic.thank you

55 years ago, I was an electronics tech in the USN. I worked on a transmitter the AN/WRT2 there were 4 large rectifier tubes in the amplifier power supply, they glowed a beautiful purplish blue, while rectifying 2kv.

You got it all, you legend. Almost as legendary as Jan Beta. The marvels of nature and technology - tubes and bunnies what more can humanity ask for?

Super cool video!!

Beinga Ham radio guy, I used to have a surplus army shortwave radio from an airplane where the dynamotor was removed and the guy that gave me the setup had built a power supply to replace the old aircraft setup so it could get the proper voltages from AC mains. That power supply had a rectifier tube on it, but it was not a cool Xeonon or Mercury vapor tube. Was still cool. If memory servers, the radio needed 15 VDC and another weird voltage to operate. It was modified to pick up Amaturer frequencies as well as shortwave. Loved the video and it has been about 40 years since I had seen a tube recifier 🙂

Stellar demonstration ! Mr. Wizard would have been proud of this .

I have 3B22s xenon filled on my Colins R-278, yes they produce beautiful colors as well. I think that magic eyes are also very cool and very different in technology from the very beginning to the latest models. It might be a good topic for a future video.

I can remember doing some (usually "jury rig") repairs on old B&W valve TVs, and the tube I remember giving almost all the trouble was the 6GV8. Any time you got "frame collapse" or a lack of Vertical Hold, you could practically bank on the 6GV8 being either faulty or not connected properly (often because of a bad solder joint).

Don't know if your familiar with the channel: photonicinduction but he has a huge mercury arc rectifier that's fun to watch.

very nice mercury vaper tube and xeon tubes i use to worn in broadingcasting and we used an old Gares gy 250 transmitter on am it had i belive the 8008 tube for recitifaction at about 1400 volts and they really glowed nicely under full load.

Amazing !

We use/used six phase (3 phase centre tapped transformer input) mercury arc rectifiers - yep, they had six anodes - to supply high current (over 400A) 1500VDC for the suburban electric trains here in Melbourne Australia. I think they are all gone now with old substations being retrofitted with newer technology and with a lot of the redevelopment going on now the new substations definitely don't. I still work in the Metro railway network but not in traction division, but yes in my younger years have seen one working. Looks really cool with a train accelerating!!

The glow of the mercury vapor brought to mind gym class in the 80s and 90s. Those lights would take forever to warm up and had an odd light spectrum.

I own an Ignatron tube, it’s huge ! Cool vid!

8:33 - reminds me in a way of the getter on some 30's radio tubes I've seen, they all had this whole reflective layer (I'm guessing it's the getter?) covering the entire top of the bulb with the layer gradually fading over towards the bottom of the tube.

Super cool 🤙

Reminds me of the argon filled OC3 regulator tube that's in classic Leslie speaker tube amps like the 122.

Both cool, but aesthetically it is xenon for the win. Good show!

I ordered 872a MAR tube on ebay just because I saw this video (those things aren't cheap)! Hoping to build a circuit around it to fire it up! Love this!

you’re the kind of guy i want to pick out unique tubes to use with a guitar amp, for real

I assembled two vacuum tube circuits when I was a kid (late 70s / early 80s): a one-tube audio amplifier and a superheterodyne receiver. But since I was not a purist, I used a silicon diode instead of the rectifier tube so the 5-tube receiver was a 4-tube. 12BE6, 12BA6, 12AV6, 50C5 and 35W4 (not bought, used diode). That kind of transformer-less receiver was called "hot tail" in Brazil. Very simple kit, only AM band, no shortwave. I'd really like to find the parts to make one of these today. The tuning and IF coils are probably the hardest to find.

I love Thyratrons! I have quite a selection and haven't seen them glow in over five years.

Great photography. You could use both of them to make a very pretty full wave rectifier. :)

Hickok tube testers use a #83 full-wave mercury-vapor rectifier (with old-type 4-pin base) because of it's fixed voltage drop at a wide range of current. There was also a short-lived tweed Fender Bassman circuit that used the #83; I've seen the schematic for it but not the actual amp, although I worked on a "transitional" Bassman that had many of the same component value and circuit characteristics as the #83 version, just not the 4-pin socket for the mercury rectifier (it had a factory-stock octal socket for a 5U4). Some folks replace the #83 in a Hickok with solid-state diodes (and perhaps some dropping resistors), but I don't recommend it ---- the calibration and "accuracy" of a Hickok was designed around the #83, and a solid-state rectifier will tend to make marginal tubes read as " good". Note that the Hickok units orient the tube sideways despite the tube manuals saying to use it in vertical orientation only; it is best to allow the tester to warm up for at least 15-20 minutes before testing tubes, to allow the mercury in the #83 to vaporize before pulling B+ current through it (to prevent the #83 from arcing, though this isn't common in a Hickok where the B+ is only 150 volts anyway; that tube will last many years in this application). By the way, an 83-v isn't the same; it's a vacuum rectifier, not a mercury vapor tube.

It would be great to look at thyratrons, regulated. To show how it changes during different phases of ignition and various loads, inductive with overload included. But it's hard to simulate.

You're right, gorgeous colours... I'd love to see a full rectification on the oscilloscope...

The xenon rectifier is a beauty, both are lovely but I much prefer the see-through deeper purple color . Their usage is way more important electrically but not without some beatification.

nice look at some old rectifier tubes. I have worked on a old AM broadcast transmitter that had 12 866A tubes . 2 sets of 3 phase. had delay relay to pre heat the 866 before the HV came on. also with the modulation of transmitter the glow would dance around . also 866A give off UV so protect eyes. also some ham radio amps use 866A with 811A tubes. I have one. the Xenon can be used in place. today HV diodes are used. I like old tubes as well . many still made today. 811A, 572/B ,3- 500ZG and Fender still use KT66 and KT 88 on new amps. I like NIXI and VFD tubes. you can make video on 0A2, 0B2 ,0D3 gas voltage regulator tubes. the different gas is different color and a different voltage. also the 6E5 EYE tube and types are neat as well. today I work on 4CW2000A7 tubes 4 in a transmitter water cooled . The ATSC TV transmitter has 2 IOT tubes . Inductive output tubes, lot of tubes still in use today .

Very cool.

OD3 Tubes glow good, and you can see the power beam inside.

Beautiful, remember my RCA 8008 tube...

"It's gonna get hot!" now this is a great vid. Mr. C's lab would like it too

I didn't realize that the mercury rectifier tubes were capable of such current, that's pretty hip. There's an old substation down the road that used to rectify 600 V for the trolley buses around the city and they used mercury rectifiers, originally at least. Would have been cool to see some 600V 3-phase arc happening.

What a surprise I was just working with some Mercury Arc lamps for water disinfection

A beefy Variac feeding that transformer would serve you well in bench tests like these, and would allow you to ditch the series resistor, while also allowing you to slowly apply voltage to the filament. Love that HP oscilloscope, btw!

This is a variation of the electric arc lamp - the variation is using a different gas for the plasma, which uses less energy and probably gives a different illumination curve. The electric arc lamp isn't widely used today because the light is uncontrollably bright and harsh.

Just avoid staring too much at them, and protect your skin. Especially for the Hg valve. The nasty UV from them can hurt you fairly quickly if the envelope lets it through.

it is actually recommended to pre-heat the Xeon tube before adding HV as well. I love the glow of mercury tubes but it is also feeling a bit risky to use them if they would break open and release all that stuff in the house

I could be wrong but if I remember correctly when CuriousMarc was repairing the power supply of the teletype there were also some of these blueish purple glowing tubes in. They are awesome anyway.

Can you gus imagine how hot it must have been to work in a room full of those things running? It probably cost a small fortune to run them and cool them. Thanks for another great video!

All these years I thought it was the charge of the gas that somehow rectified AC.. "The one heated electrode".. Very good video thank you for teaching me this.. Looking at an "RCA IK3" hv tube I purchased a lot online for like 10 bucks. Amazing how the high vacuum allows electrons to flow but not breakdown.. The glass shell glows, guess it conducts better.. Awesome bygone technology that is excellent for HV tinkering.

As an autistic person I find radio tubes just so fascinating.

Am really looking forward to the next time you fire up the Centurion for another experiment/project !!!!!!!

Tubes are so cool

Awesome 😎

I have some NOS 866As (half-wave filament type mercury vapor rectifier), and they come with warning labels in their boxes. "Warning, preheat tube for minimum of 60 minutes at first installation" and, more importantly "CAUTION X-RAYS. This device may produce X-rays when energized. Operation personnel must be protected by appropriate shielding. X-ray warning signs or labels should be permanently attached to equipment directing operating personnel never to operate this device without X-ray shielding in place."

The 3B28 was designed to replace the 866A.

I know virtually nothing about tubes relatively speaking but it seems like it makes sense in my head that Xenon gas would sink less voltage than mercury vapour. Either because of the phase or the density or because it's a noble gas or some combination of reasons. Fascinating either way.

Yeah! Now all you need is two big electrolytic caps, a power resistor, and you have your radio's +B.

I was really hoping to see a full wave rectifier made from these operating together, but oh well, they're still cool (hot? Those filaments do get damn hot) as hell individually.

Tasty, tasty UV from that mercury rectifier XD

The waveforms of each tube were about the same, but the way they turned on looked a little different. Both have a cliff at the front, indicating it has to pass some threshold to conduct -- makes sense. The mercury (11:00) appears to grow upward. The whole half-wave is present from the start (except the threshold), and the magnitude grows over a few seconds. The xenon (12:16) appears to grow from the back. It starts as the the tail end of the wave, with the cliff near the end. Then the cliff moves forward as the voltage grows. Does anyone have an explanation for this difference? It looked like the scope may have been set to trigger on falling edge for the mercury and rising edge for the xenon. But I haven't used analog scopes enough to understand how triggering works on them, and whether this would explain it.

Love the plasma color 😍📻⚛

I have these tubes in a high voltage generator that we use for calibration. I was curious about the glowing coming out of this generator tubes but now I have an idea of what it might be.

very interesting. I'd love to see an application for that tube.

きれいな光。

It is the same process/discharge (with different details) you also see in the TL tubes.