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.
How many volts were they rectifying for the arc lamps? (If it was over about 15kV, then you'd ALSO get a bit of X-Ray radiation to add to you UV). The glass envelope itself probably blocked a majority of the UV from escaping (but some WILL get out though) Here in NZ, we _USED_ to use MARs (Mercury Arc Rectifiers) for the HVDC submarine link between the two main islands. Unfortunately, they've now been fully converted to Thyristors. You can see a pic or the MARs bank halfway down the page at: en.wikipedia.org/wiki/HVDC_Inter-Island Just imagine getting too close to THOSE puppies when they were active!!! LOL My understanding is that the inter-island HVDC link currently employs two independent 'poles' each operating at 350kV DC at up to 2000A (That should get that slice of toast ready nice and quickly!)
Ran xenon short arc lamps on our 35mms, and you still don't take those power supplies lightly. I can only imagine carbon arc with these tube rectifiers. Always wanted to try my hand at the carbon arc projectors but sadly it's a dying art.
Man, that's awesome! When things get to the high power level, there's some seriously impressive tube equipment out there! As Trevor said the majority of the UV should be blocked by the glass enclosure (especially so on this comparatively tiny little rectifier).
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 UA-cam appeared. Photonicinduction was the channel. Well THAT took a turn! So cool to see here a smaller version! Thanks for this!
SE4 is a GREAT game. I remember exactly what mission you're talking about, too. First time o ever saw one was in a video on YT, it was in a battery charger, and to start it you turned a knob on the front that tilts the whole tube to strike the arc in it. It was super cool.
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
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.
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.
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.
@@UsagiElectric Interesting property, I wonder if that was ever exploited in the same way SCR and TRIAC is for "dimming" in whatever context it might have been used in Edit: as it seems to be related to filament temp as well
there is a small reverse current that is not seen in the scope. the reverse current will be approx in the ratio of electron mass vs Hg ion mass. The contribution of Hg ion to the total current is rather small (also space charge)
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👍
Right! They're just gorgeous little tubes when lit up, and while the original designers probably viewed it as an unwanted side effect, to me, it's the primary reason to use them.
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 🙂
50 years ago as a kid in high school I worked at the local radio station. We had a 10KW FM transmitter, old RCA thing, that used 6 mercury vapor rectifier tubes for the B+. In the winter time we always left the filaments on even when it was off the air as the transmitter shack up on the mountain was unheated. Mercury would condense on the cathodes and the plates in cold weather. Every once in a while the goofball who worked the last shift on Saturday night, in a hurry to leave, would kill all the power. The Sunday morning person couldn't get the station on the air and I would get a phone call early before church. Headed to the station to get the jeep for the trip up the mountain and afraid of what I was going to see. Yep, instant superfund site, all the rectifier tubes had exploded. I don't miss working with these.
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.
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.
Oh yeah, Marc's TTY power supply was an absolute gorgeous piece of equipment! And the little usagi quickly discovered the tube wasn't going to supply any treats and lost interest, haha.
I have some 2D21 thyratrons here somewhere, as well as some miniature pencil size thyratrons that were used in televisions. I used to have some larger ones that were used for elevator switching I think but I don't know where those have gotten to.....
I'm so used to associating the word "rectifier" with bridge rectifiers that I forget that technically a single diode is technically a sorta crappy rectifier all by itself - you only get half of the wave though, whereas a bridge rectifier flips the bottom half of the wave and sticks it upstairs with its counterpart. Those big mercury arc rectifiers are really something to watch! Depending on the glass used, they could even be a serious source of UV radiation but I'm not sure. Cool video, I like your channel man.
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 👍
Thank you! Interestingly, the big Mercury Arc Rectifiers are actually a little different. They're technically a cold cathode tube that uses a pool of mercury in the bottom of the tube as the cathode. They're brilliantly designed tubes, and if I can ever get my hands on one, I'd love to do a deep dive on them!
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 👁️🗨️
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.
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
The much larger mercury tubes are actually a little different. Those are Mercury Arc Rectifiers, and interestingly, they don't have a filament, making them a cold cathode tube. But the cathode is actually the pool of mercury in the bottom. They're amazing pieces of engineering and I'd love to get my hands on one someday!
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.
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.
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.
mercury arc rectifiers were used when we needed currents of 1000 or 10000A for example for use in electrolysis for metal production (Al, Mg, Na, K etc etc)
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.
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.
I was thinking the same thing! I just didn't mention it in the video because I guarantee I would ended up confusing myself and saying the wrong words at the wrong times, haha.
You are probably thinking of 01 or 01A directly heated, battery-radio triodes with 4 pin bases.. Some of the earliest ones, even brand new, had a rainbow effect to the getter that did not signify that they were heavily used or about to wear out. Somebody offered me a bunch of them in boxes at a moderate price and I assumed that they were used and didn't buy them. That was a mistake as I could have easily doubled or more than doubled my money on them, but it was early into my days of reselling tubes and there was a lot I did not know. Not to mention, that particular antiques seller tended to be overpriced on most things and drovre a hard bargain, which made me leary.
@@goodun2974 I don't really remember what these were (I'm talking about something I saw some 15 odd years ago when I was a lil' kid), but the 4-pin base does ring a bell to me
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
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. :)
In the early 90s the factory i worked in had a machine for welding mesh that had quite a few of thise mercury vapor rectifiers. They were quite a sight.
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.
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.
Very keen eyes! The real reason they look different when powering on is because I'm colossally lazy, haha. With the Mercury tube, I pre-heated the tube for around a minute before applying any high voltage. But, when I switched over to the Xenon tube at 12:16, I was in the groove for filming and didn't want to wait to pre-heat the tube, so I just slapped it together and hit the switch. In the edit, I cut out the approximate 15 seconds it took for the heater to warm up enough to start the ionization process. Having said that, the Xenon tube does tend to have the cliff start at the tail end and move forwards while the mercury tube doesn't. Both tubes do get a full rectification and then grow in amplitude over the next 30 seconds or so after ionization starts. I don't have a good explanation for why the cliff start at the tail end and moves forwards though, that's a really interesting phenomenon that I imagine is related to the different ways that the Xenon and Mercury ionize.
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.
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.
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!
Water jackets….pump and plumbing…..pond with a lovely spray water fountain I used wonder why the power radio stations had such beautiful lands scraping…..then one day, while looking at 22 inch tall water cooled 50,000 watt output tubes, the light bulb in my head begin to glow “DUH, closed loop evaporative cooling”…bet those power and transmitter rooms were sweat boxes
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).
That mercury vapour tube has the whitest of white glows just before it changes to pale blue. It reminds me of a dream I can still remember from when I was a child. I never expected to actually see such a pure white in real life. I'd thought it only existed in my dream. Bunny: Where's more food? More food, I say! This isn't edible! I'm out'a here!
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.
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.
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!
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 have several itams with magic eyes in them one a zenith radio an also a old stereo reel to reel deck that records stereo only in one direction as it uses the whole 1/4" tape half for each channel. It has two magic eyes both of those the zenith tombstone radio anfd the tape deck work well. I have not recaped them so it a miracle they are working so good. I dont turn them on much because i do plad on recapping them before they have a problem.
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!!
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 .
You're absolutely right! But these rectifiers do have a 15V drop across them according to the datasheets, so I would be expecting about 140V to 145V peak on the scope, but in reality, it looked a little closer to 130V to 140V. Could just be my poor reading of the scope though, I really should have dropped the V/cm setting and put 0V at the bottom of the grid and then use the full grid to count the real amplitude.
There are various gas-filled regulator tubes - the most easily-identified ones are in the "zero" series: 0D3, 0C3, 0A2. There is no cathode heater, hence the 0-volt designation. Also of interest, if you can find one, is the 0A4G cold-cathode triode. There are some very interesting applications suggested for that one in the RCA datasheet. (Such as remote control of line voltage via RF signals transmitted through the line being switched)
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.
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!
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 know, that is actually something I've wanted to play with for a while. Using phase shifting on the grid of a thyratron to build an adjustable and/or regulated power supply, but you're right, it's pretty tough to get it just right. Plus, the little 2D21 thyratrons I have aren't quite up for power supply duty. Hmm, time to hit eBay for some bigger thyratrons...
@@UsagiElectric i have only heard of it in my middle shool. In the meantime I loved vacuum technology. In the old days I have ridden in electrical grid busses that used it. No way to watch them - closed somewhere in the back. Only stories. It would be beautifully satisfying to watch them work sililarly like in the stories!
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.
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.
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.
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.
Hahaha thousands of tubes! You are like me , you buy tubes I buy analog meters (needle ones) I simply love.them, I buy them and later figure it out what to build so I can use them xD The xenon tube es awesome! I also love the glow of the thyratrons! Don't know if you have any laying around , I bet you got a collection of them xD Looking forward 4 your next vid,.tkz
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.
There's another style of gas-discharge tube in this vein which behaves more like a zener diode, those continued to crop up even as things became more solid-statey over time so it might have been one of those.
Very interesting Video as always. You made me want to get into a new lot of beat up old tubes😅 Careful with the mercury rectifier, that's gonna emit UV. In military and industrial type noble gas filled tubes they sometimes used a radioactive isotope to give the tube that little bit of energy to trigger the ionization. Often that was xenon 80 I think so that should be long gone with its half life of 10 or so years. Without that isotope the gas needs an external source of trigger energy, usually some sort of UV light so in complete darkness such tubes often don't work right
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.
were 6AU6s very common over there? in the UK it was EF50 first, many were available as ex radar surplus after the war, then EF91/6AM6, bucketloads were also available as surplus/cheap in the 50s to early 60s, and eventually EF80/6BX6, these were used in pretty much all valve tvs until replaced by the later EF183 and EF184 , there was 6AU6s/EF94s over here but not that much used, EF93/6BA6 more so
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.
How do you get steady flow? Like getting rid of the AC all together. I think this is the first time I found out that AC was a sine wave. I feel like this should be obvious to me but it isn’t. would you use two rectifiers? Help me out.
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.
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.
How many volts were they rectifying for the arc lamps? (If it was over about 15kV, then you'd ALSO get a bit of X-Ray radiation to add to you UV).
The glass envelope itself probably blocked a majority of the UV from escaping (but some WILL get out though)
Here in NZ, we _USED_ to use MARs (Mercury Arc Rectifiers) for the HVDC submarine link between the two main islands. Unfortunately, they've now been fully converted to Thyristors.
You can see a pic or the MARs bank halfway down the page at:
en.wikipedia.org/wiki/HVDC_Inter-Island
Just imagine getting too close to THOSE puppies when they were active!!! LOL
My understanding is that the inter-island HVDC link currently employs two independent 'poles' each operating at 350kV DC at up to 2000A
(That should get that slice of toast ready nice and quickly!)
Rectron rectifiers? Found another video of these used with a cinema arc projector.
Ran xenon short arc lamps on our 35mms, and you still don't take those power supplies lightly. I can only imagine carbon arc with these tube rectifiers. Always wanted to try my hand at the carbon arc projectors but sadly it's a dying art.
Greetings fellow (former) projectionist
Man, that's awesome! When things get to the high power level, there's some seriously impressive tube equipment out there!
As Trevor said the majority of the UV should be blocked by the glass enclosure (especially so on this comparatively tiny little rectifier).
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 UA-cam appeared. Photonicinduction was the channel. Well THAT took a turn! So cool to see here a smaller version! Thanks for this!
SE4 is a GREAT game. I remember exactly what mission you're talking about, too. First time o ever saw one was in a video on YT, it was in a battery charger, and to start it you turned a knob on the front that tilts the whole tube to strike the arc in it. It was super cool.
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
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.
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.
its almost grey right
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.
Yup! Takes about 15V to 20V before the ionization occurs and it begins conducting properly.
@@UsagiElectric Interesting property, I wonder if that was ever exploited in the same way SCR and TRIAC is for "dimming" in whatever context it might have been used in
Edit: as it seems to be related to filament temp as well
there is a small reverse current that is not seen in the scope. the reverse current will be approx in the ratio of electron mass vs Hg ion mass. The contribution of Hg ion to the total current is rather small (also space charge)
These old tubes are a strong reflection of the creative genius that created these devices !!
I often struggle to wrap my head around these things, but those mad lads invented the things!
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.
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👍
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.
Right! They're just gorgeous little tubes when lit up, and while the original designers probably viewed it as an unwanted side effect, to me, it's the primary reason to use them.
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 🙂
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?
Always fun to do !...cheers.
50 years ago as a kid in high school I worked at the local radio station. We had a 10KW FM transmitter, old RCA thing, that used 6 mercury vapor rectifier tubes for the B+. In the winter time we always left the filaments on even when it was off the air as the transmitter shack up on the mountain was unheated. Mercury would condense on the cathodes and the plates in cold weather. Every once in a while the goofball who worked the last shift on Saturday night, in a hurry to leave, would kill all the power. The Sunday morning person couldn't get the station on the air and I would get a phone call early before church. Headed to the station to get the jeep for the trip up the mountain and afraid of what I was going to see. Yep, instant superfund site, all the rectifier tubes had exploded. I don't miss working with these.
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.
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.
I was about to write the same ;)
Oh yeah, Marc's TTY power supply was an absolute gorgeous piece of equipment!
And the little usagi quickly discovered the tube wasn't going to supply any treats and lost interest, haha.
I have some 2D21 thyratrons here somewhere, as well as some miniature pencil size thyratrons that were used in televisions. I used to have some larger ones that were used for elevator switching I think but I don't know where those have gotten to.....
Love valves, thanks for this. Still got my Tektronix 2215 60Meg scope. A reliable companion for many years.
Stellar demonstration ! Mr. Wizard would have been proud of this .
I'm so used to associating the word "rectifier" with bridge rectifiers that I forget that technically a single diode is technically a sorta crappy rectifier all by itself - you only get half of the wave though, whereas a bridge rectifier flips the bottom half of the wave and sticks it upstairs with its counterpart. Those big mercury arc rectifiers are really something to watch! Depending on the glass used, they could even be a serious source of UV radiation but I'm not sure. Cool video, I like your channel man.
I love the old VT127A and the 327A. They both have the uranium glass pin pass throughs! Great video.
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 👍
Thank you!
Interestingly, the big Mercury Arc Rectifiers are actually a little different. They're technically a cold cathode tube that uses a pool of mercury in the bottom of the tube as the cathode. They're brilliantly designed tubes, and if I can ever get my hands on one, I'd love to do a deep dive on them!
We used to use mercury arc rectifiers in telephone exchanges to keep the 50 volts batteries charged.
that was a trip down memory lane. very nostalgic.thank you
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 👁️🗨️
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.
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
Beautiful. I didn't know mercury vapor rectifiers came in such a small package.
The much larger mercury tubes are actually a little different. Those are Mercury Arc Rectifiers, and interestingly, they don't have a filament, making them a cold cathode tube. But the cathode is actually the pool of mercury in the bottom. They're amazing pieces of engineering and I'd love to get my hands on one someday!
@@UsagiElectric i was gonna ask if it was the same principle with the big mercury rectifiers. Question answered.
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.
tall tubes were high voltage but relatively low current rectifiers. 3ft rectifiers were common for x-ray tubes etc
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.
if you do not have the tracks as the return path, you will need two pantographs and two wires on the top...
@@janami-dharmam Yeah, two "sticks" www.lubus.info/images/stories/technika/siec/3839-153-2011-3.jpg
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.
mercury arc rectifiers were used when we needed currents of 1000 or 10000A for example for use in electrolysis for metal production (Al, Mg, Na, K etc etc)
Also used to rectify current for railway trains, I think one is in use in one of the UK islands.
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.
Enjoyed this look at rectifier tubes. I never know what to expect from your channel but it's always interesting!
Thank you!
I've been going so hard on the Centurion lately, I needed a little change of pace. :)
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.
You're right. The getter flash after the tube is evacuated.
I was thinking the same thing! I just didn't mention it in the video because I guarantee I would ended up confusing myself and saying the wrong words at the wrong times, haha.
You are probably thinking of 01 or 01A directly heated, battery-radio triodes with 4 pin bases.. Some of the earliest ones, even brand new, had a rainbow effect to the getter that did not signify that they were heavily used or about to wear out. Somebody offered me a bunch of them in boxes at a moderate price and I assumed that they were used and didn't buy them. That was a mistake as I could have easily doubled or more than doubled my money on them, but it was early into my days of reselling tubes and there was a lot I did not know. Not to mention, that particular antiques seller tended to be overpriced on most things and drovre a hard bargain, which made me leary.
@@goodun2974 I don't really remember what these were (I'm talking about something I saw some 15 odd years ago when I was a lil' kid), but the 4-pin base does ring a bell to me
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
in a dark room, many things will show fluorescence because of the lot of UV produced - but they are bad for the eyes.
Looking forward to more videos on particular or unusual tubes.
you’re the kind of guy i want to pick out unique tubes to use with a guitar amp, for real
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. :)
"It's gonna get hot!" now this is a great vid. Mr. C's lab would like it too
this is great, glad to have discovered your channel! Great explanation at the beginning.
Beautiful LEDs :D
In the early 90s the factory i worked in had a machine for welding mesh that had quite a few of thise mercury vapor rectifiers. They were quite a sight.
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.
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.
Great photography.
You could use both of them to make a very pretty full wave rectifier. :)
Thank you!
I actually did think about this, but I didn't have enough alligator clips, haha.
@@UsagiElectric LOL.
Great video! Excellent camera work!
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.
the only difference i see in the ‘scope is the sweep period, so i don’t think it’s the triggering
maybe something to do with the thermal stuff?
Very keen eyes!
The real reason they look different when powering on is because I'm colossally lazy, haha.
With the Mercury tube, I pre-heated the tube for around a minute before applying any high voltage. But, when I switched over to the Xenon tube at 12:16, I was in the groove for filming and didn't want to wait to pre-heat the tube, so I just slapped it together and hit the switch. In the edit, I cut out the approximate 15 seconds it took for the heater to warm up enough to start the ionization process.
Having said that, the Xenon tube does tend to have the cliff start at the tail end and move forwards while the mercury tube doesn't. Both tubes do get a full rectification and then grow in amplitude over the next 30 seconds or so after ionization starts. I don't have a good explanation for why the cliff start at the tail end and moves forwards though, that's a really interesting phenomenon that I imagine is related to the different ways that the Xenon and Mercury ionize.
@@UsagiElectric I was wondering about the same thing. Quite interesting to see the different behavior.
the scope triggering was not stable and the display was not rock steady. what you saw is an artifact of the trigger setting, I guess.
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.
A very lovely glow!
Absolutely fascinating! Plasma!! Wow, so cool!! 🤩
After second consideration I will start working with tubes. Nostalgia level off the charts here.
Reminds me of the argon filled OC3 regulator tube that's in classic Leslie speaker tube amps like the 122.
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.
They look amazing.
You're right, gorgeous colours... I'd love to see a full rectification on the oscilloscope...
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!
Water jackets….pump and plumbing…..pond with a lovely spray water fountain
I used wonder why the power radio stations had such beautiful lands scraping…..then one day, while looking at 22 inch tall water cooled 50,000 watt output tubes, the light bulb in my head begin to glow “DUH, closed loop evaporative cooling”…bet those power and transmitter rooms were sweat boxes
Both cool, but aesthetically it is xenon for the win. Good show!
A good youtuber
Correction a great youtuber
Old vaccuum tubes are so cool to me, i love them.
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).
That mercury vapour tube has the whitest of white glows just before it changes to pale blue. It reminds me of a dream I can still remember from when I was a child. I never expected to actually see such a pure white in real life. I'd thought it only existed in my dream.
Bunny: Where's more food? More food, I say! This isn't edible! I'm out'a here!
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.
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.
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!
I still have an old 60s Telerad Vacuum tube radio somewhere that my Dad bought with his first salary!
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 have several itams with magic eyes in them one a zenith radio an also a old stereo reel to reel deck that records stereo only in one direction as it uses the whole 1/4" tape half for each channel. It has two magic eyes both of those the zenith tombstone radio anfd the tape deck work well. I have not recaped them so it a miracle they are working so good. I dont turn them on much because i do plad on recapping them before they have a problem.
Tremendous video, keep it up champ!!
I own an Ignatron tube, it’s huge ! Cool vid!
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!!
Don't know if your familiar with the channel: photonicinduction but he has a huge mercury arc rectifier that's fun to watch.
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 .
Just a reminder, 113VAC (RMS) would be close to 160V peak.
Just a reminder, this type of rectifier have average voltage drop around 15V
@@petrjiricek8039 A shottky mercury vapor rectifier should perform better
You're absolutely right! But these rectifiers do have a 15V drop across them according to the datasheets, so I would be expecting about 140V to 145V peak on the scope, but in reality, it looked a little closer to 130V to 140V. Could just be my poor reading of the scope though, I really should have dropped the V/cm setting and put 0V at the bottom of the grid and then use the full grid to count the real amplitude.
@@UsagiElectric That's assuming the scopes are calibrated. ;)
I love Thyratrons! I have quite a selection and haven't seen them glow in over five years.
0:28 - do you have a video explaining why the 6AU6 is your favorite?
He built an entire vacuum tube computer out of them. Check out the videos...
OD3 Tubes glow good, and you can see the power beam inside.
There are various gas-filled regulator tubes - the most easily-identified ones are in the "zero" series: 0D3, 0C3, 0A2. There is no cathode heater, hence the 0-volt designation. Also of interest, if you can find one, is the 0A4G cold-cathode triode. There are some very interesting applications suggested for that one in the RCA datasheet. (Such as remote control of line voltage via RF signals transmitted through the line being switched)
Beautiful, remember my RCA 8008 tube...
Am really looking forward to the next time you fire up the Centurion for another experiment/project !!!!!!!
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.
Tubes are so cool
Agree, I wish I could have access to this sort of tech
Can you make a full bridge rectifier with these?
Yes, but you need at least 3 separate filament transformer windings.
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!
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 know, that is actually something I've wanted to play with for a while. Using phase shifting on the grid of a thyratron to build an adjustable and/or regulated power supply, but you're right, it's pretty tough to get it just right. Plus, the little 2D21 thyratrons I have aren't quite up for power supply duty. Hmm, time to hit eBay for some bigger thyratrons...
@@UsagiElectric i have only heard of it in my middle shool. In the meantime I loved vacuum technology. In the old days I have ridden in electrical grid busses that used it. No way to watch them - closed somewhere in the back. Only stories. It would be beautifully satisfying to watch them work sililarly like in the stories!
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.
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
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.
The 3B28 was designed to replace the 866A.
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.
Hahaha thousands of tubes! You are like me , you buy tubes I buy analog meters (needle ones) I simply love.them, I buy them and later figure it out what to build so I can use them xD
The xenon tube es awesome! I also love the glow of the thyratrons! Don't know if you have any laying around , I bet you got a collection of them xD
Looking forward 4 your next vid,.tkz
Super cool video!!
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.
There's another style of gas-discharge tube in this vein which behaves more like a zener diode, those continued to crop up even as things became more solid-statey over time so it might have been one of those.
Very interesting Video as always. You made me want to get into a new lot of beat up old tubes😅
Careful with the mercury rectifier, that's gonna emit UV. In military and industrial type noble gas filled tubes they sometimes used a radioactive isotope to give the tube that little bit of energy to trigger the ionization. Often that was xenon 80 I think so that should be long gone with its half life of 10 or so years.
Without that isotope the gas needs an external source of trigger energy, usually some sort of UV light so in complete darkness such tubes often don't work right
The glass envelope blocks virtually all of the UV it generates, I wouldn't worry about it
@@gideonwackers7693 yeah I guess you're right. I highly doubt it's made of quartz glass, didn't think about that
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.
It is the same process/discharge (with different details) you also see in the TL tubes.
were 6AU6s very common over there? in the UK it was EF50 first, many were available as ex radar surplus after the war, then EF91/6AM6, bucketloads were also available as surplus/cheap in the 50s to early 60s, and eventually EF80/6BX6, these were used in pretty much all valve tvs until replaced by the later EF183 and EF184 , there was 6AU6s/EF94s over here but not that much used, EF93/6BA6 more so
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.
Hey again! I still have the kit's schematics! www.dropbox.com/s/r8ze2e6jpzkw3a5/20220815_232724.jpg?dl=0
How do you get steady flow? Like getting rid of the AC all together. I think this is the first time I found out that AC was a sine wave. I feel like this should be obvious to me but it isn’t. would you use two rectifiers? Help me out.
very interesting. I'd love to see an application for that tube.
Thanks for sharing, looks cool indeed. If you'll rectify the AM signal, will the plasma be blinking in sync with music? :)
Yes. Totally. I saw that on photonicunductions channel
As an autistic person I find radio tubes just so fascinating.
That was spectacular. Any idea on the temperature reached in the plasma? And the tube itself?
Amazing !
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.
Why the beginning of each half-wave is cut, in the oscilloscope?