What a highlight to my day to see you talking about this bulb! I don't know if you've seen my video about re-creating a carbon filament lightbulb, but I did a solid few years of research and experimentation to make it happen. Quite an obsession for me. The carbon lightbulb is an invention that's right out of an era where the technology is such that I can wrap my mind around it. After the early 1900's technology starts getting over my head fast. To answer what the filament is made from, it's almost certainly extruded from a mixture of graphite or carbon black paste, bound together with nitrocellulose or a similar organic substance, and carbonized in place already pre-attached to the leading wires of the lightbulb. A glob of carbon paste is used to stick the filament to the metal wires before carbonizing, which gives the delicate carbon a solid physical and electrical connection (a hard thing to achieve between the mechanically dissimilar materials). Besides extruded filaments, the only other options commonly used were either paper or bamboo. It's pretty easy to identify a paper filament, though bamboo can look a lot like an extrusion to the naked eye, complicated by the fact that bamboo filaments were smeared with a carbon paste which would look identical from the outside to an extrusion. You may need to snap a filament and look for evidence of wood grain in the center under a microscope to be absolutely sure. One last interesting thing that was done to improve the life of filaments was to fire them up for the first time in an extremely hydrocarbon rich atmosphere before the bulb was blown over the outside. This caused the hydrocarbons to deposit and carbonize on the surface of the filament, filling any voids and imperfections. In areas where the filament was too narrow it would heat up faster causing more carbon to deposit and even out the difference. Really brilliant solution to improve consistency. Love seeing this bulb in action. I haven't dared to fire up the two carbon bulbs I purchased during my re-creation process.
I found a huge treasure trove of old bulbs in New Zealand in the early 80s. These were in an old movie theater near Wellington the capital city. Most of these were from the thirties and were colored glass for the theater mood lighting that was standard in the old days. A few were older and had the pointed Pontil end on top, and clear glass. Don't know how many were really old, but there were hundreds and they were rare even then. No idea what happened to them all, but I sold a lot to a curiousty shop in Cuba street. I still have a lot of old fittings and early lamps and stuff. Your comment is really interesting. Cheers.
I was going to ask Fran if she is sure this is a carbon filament bulb, and not a metal filament one, because the filament attachement point to the incoming leads looks like welding. They can be a blob of carbon paste, though. Although the one on the right side feels too thin to me for being a carbon blob that still holds it together after 100+ years.
@@mrnmrn1 Yes, its definitely a carbon filament. The carbon putty used to glue the filament to the leads becomes one unified piece of graphite, one piece with the filament when it's fired. It's a great way to join metal to carbon. For metal filaments welding was hardly if ever used because it's easier to clamp. Those didn't come until several decades later though, when forming thin tungsten wire became possible.
paper filaments? how in the world did they not burn up? I've heard of bamboo filaments before but cant wrap my head around that either, how would they produce such a thing string of bamboo?
@@SpydersByte They were carbonized, basically turned into charcoal then heated further turning the charcoal into graphite. In my video recreating the filaments I used both cotton string and paper with success. Some of the best advances to filament technology came from a guy called Lewis Latimer who invented a reliable way to mass produce paper filaments, though bamboo was still I think dominant for the early years, then extruded filaments probably using a variation of Latimer's process to carbonize them.
The original Shelby bulb was first manufactured in the 1890s. There is one bulb which is currently lit at fire station number 6 in Livermore, CA. The bulb has been on for over 1,000,000 hours and is in The Guinness World Record book for its long life. Great bulb Fran : )
@@deadfreightwest5956 This is absolutely true, however a modern bulb also puts out significantly greater light at lower consumption. But ends up being a disposable item. What's been very disappointing to me is the supposed extreme long life of LED bulbs and quite frankly most of them end up failing sooner than incandescent did. It's not usually the LED itself that fails it's always the crappy electronics that drive it or poor solder connections. Fortunately they've gotten cheap enough at this point but it kind of doesn't matter financially but it still bothers me that it's wasteful and stuff gets tossed in a landfill that should still be operating.
@@Darkk6969 I've had a little better luck than that with the cheaper LED bulbs, at least the ones you get at home depot that replace incandescent bulbs with your standard light bulb. where I've had terrible luck with LEDs tend to be things like stuff off of Amazon or ebay . Inexpensive solar outdoor lights some of them not that inexpensive. Inexpensive LED flashlights. Things like that and very rarely is it actually the LED that fails it's usually a crappy solder joint or some secondary electronic component like a capacitor etc or in the case of solar lights the battery craps out.
Cant believe anything CA government says. Use to ride my motorcycle up in that there. There is a top secret rocket base hidden back in there. I use to see rockets fired at night every so often so i went looking,
About 15 years ago they were renovating a high school in my area and during the high school renovation I managed to acquire about eight of those exact Ti calculators....I acquired them out of a dumpster which I thought was pretty sad but they all worked....
@@awesomeferret I'm not sure that's even true but how good do you think a modern plastic device is going to feel 50 years from now? Oh yeah it won't still be around because it'll long ago have been in the landfill.
The old factory of the Shelby Lightbulb company is now a surplus store that I frequent. I've been told that upstairs in the old factory building is still some of the equipment they used to make the light bulbs.
GET. SOME. PHOTOS. GIVE THEM. TO. FRAN. That sounds super cool. Sounds like a neat thing to see and I don't see why they would have an issue with it if you frequent the store. Fran would probably think its super cool too. Cool channel I gave you a sub. I think its neat that Fran gets so many creators that frequent her channel. She really is one of the greats on here.
@@bigjd2k Yup, take your 120v 1,000h bulb and run it at 110v and you'll get 3,000h out of it. Run it at 100v and get 10,000h but also a 27% reduction in efficiency. So for a bulb that costs 1$ to buy but uses 10x as much dollars worth of electricity during its life I think it's better for them to be as efficient as possible.
A Poloroid® filter on the camera lens would only help with reflections if the light source causing the reflections is also polarised, and it’s at the right angle.
Remarkable difference between carbon and tungsten filament lightbulbs: a tungsten lamp will always break when you switch it on, a carbon lamp will break while it is on and on operating temperature. Positive vs negative temp coefficient.
Ahh. I thought she made a mistake when she said the resistance drops when it's hotter. That's something new I learned today. Thank you. So I guess when one of these fails, its almost like an un-ballasted HID lamp - In that it gets hotter, draws more current and has a runaway effect. I can imagine that this made the carbon filament lamps much more difficult to design. Tungsten has a limited capability to regulate itself to an extent.
Sometimes tungsten fails during operation, and it can be quite fun. I've seen one example up close about 10 years ago. The filament opened at one end, but continued to operate. The only thing I realised was a weak, about 400Hz tone coming from the lamp. When I went closer I could see a small, bright blue arc where the filament broke. The arc held together the filament for about 10-20 minutes!
It is a work of Art. It reminds me of a story my grandfather told me when I was about 11 or 12; He was in Montreal, during the McGill university riots. He was standing beside a Surete Du Quebec officer, watching the fires and students smashing a large computer. A vacuum tube, flew or rolled up to my grandfather's feet, and he bent over, picked it up, and asked the cop if he could have it as a souvenir. "You can `ave, is garbage now" He labelled it and kept in a pill bottle. I inherited it after he died. He also while in Quebec, visited one of the Mines there, and told me it was opened in 1800 something, and that "most" of the original (Carbon Filament) bulbs, were still lit, working, and never switched off. "They've been lit for (nearly or definitely) 100 years". I have one very similar to what was in the Mine. It was never used, but unfortunately, the tip was broken, so it's just a memento.
@@randymack1782 The bulbs are made, but they put tungsten filaments in them and run them at lower voltage to replicate the carbon look. I spoke to the curator of the Menlo park exhibit at greenfield village for some time about where their replica bulbs were made and how they work. As far as I know nobody is still making real carbon filament bulbs besides people like myself doing it just as a hobby to explore the science.
People were terrified of light bulbs and electricity took over 20 yrs for it to be accepted Gramps wood not put in power till after he died and dad put in power in 1946
Haters are hard to understand. I don't get how this got any downs. Do they hate electrons? Digital Multi Meters? Filaments? It can't be photons, can it? It must be Variacs™ that are hated !
@@therugburnz you know i have thought the same thing many times on all kinds of videos and i think i have come up with an answer as i, myself every now and then accidentally hit the dislike on my touch devices. I want to believe I've noticed it every time and undone it. But its very possible I've missed a few and left some dislikes behind. I assume the same things happen to the like button so i think the ratio of likes/dislikes is the only thing to go by.
I have strings of series-wired 15 Volt carbon filament Christmas lights. I believe they are from the early 1900s. All of them still work today, and there are boxes of spares. They get hot like crazy, especially the blue and red, but I guess this would be considered 'safer' than candles !
These bulbs are to cool! I was lucky enough to acquire a working Shelby bulb too “now under glass.” They are a neat and important part of lighting history.
Fantastic! The oldest bulb in my collection is only about 75 years old, and I know a guy who has a bulb that was saved from WW1, from the British trenches in France. It's dated as 1915, both on the glass bulb, and on the carton. I wish I could remember the manufacturer, but I'd only be guessing now. I did once hold that bulb, and it was a strange feeling, holding a fragile piece of history. I asked him "How much" but it wasn't for sale at any price. It was his dad's before him, and he took possession of the bulb along with his dad's electrical repair shop when the old man retired. The bulb lived on a shelf in the shop along with a myriad more vintage electrical artefacts. I was able to buy a few of the lesser items from his collection, but nothing like this little lamp of yours. It's hard to fathom that electric lighting goes back so far, and that candles and oil lamps remained staples of domestic and commercial lighting for so long after. Indeed, some isolated places not far from me didn't even see an electric light until the early 1980's! I've seen the Centennial bulb, and amazing as it is, it is quite seriously under-run and will probably outlast the planet! It is safely tucked away in a quiet corner of the fire station where no one and nothing, short of an earthquake, will ever disturb it. It is well looked after!
@rogerwilco99 I understood how to use a slide rule for about two weeks in high school in 1973, then promptly forgot everything when the powers that be decided to allow calculators in class. My first was the SR-10, and doing squares and square roots was endlessly entertaining! My early TIs from high school and college are long gone, but I have an HP-12C in (almost) daily use since 1984...those things are built like tanks!
Hi Fran, am a light bulb collector of the incandescent type. What a beautiful Mushroom Shaped light bulb. I do have a lot of these from Osram. "I bought these from ebay and got a good collection of Mushroom Opal Light bulbs which are milky white in colour and beautiful when lit." They are quite pleasing to the eyes as well. A nice soft white light. Thanks for showing us your video it was very interesting to watch.
Love your obvious pleasure in this little rarity. I share your pleasure in various vintage bulbs big and small in my collection. It's amazing that some can see beauty in what others perceive as old junk.
LED bulbs exist today at your local big box hardware store that provide the aesthetics of these bulbs, but with a much higher efficiency. I have one over my sink. it's quite nice.
I have one in the porch lamp on my house here in the UK, which was built in 1899. (The lamp itself is an original 1940s cast aluminium swan-necked corner fitting by Coughtrie of Glasgow, who still make lighting today, including a modern version of my lamp). It has a lovely teardrop-shaped clear glass shade full of little wobbles and imperfections. The bulb I bought for it is LED but has the little nipple on the top and puts out a lovely warm glow that's a nice contrast to the modern cold while LED street lighting recently installed in my neihhbourhood.
Thanks Fran. You light up our lives! Your curiosity and appreciation for often legacy technology is infectious. And your laugh/chuckle is the most endearing ever. 🥰 Lovin it in Canada! 🇨🇦
Fran, I just have to say that I absolutely love your voice. At the start of your videos when you say "hi it's Fran in the Franlab", it never fails to bring a smile to my face. It's comforting, almost like singing or something. Anyways just wanted to tell you how much I appreciate your videos. I'm always enthralled by your content.
That is extremely cool! I happen to have one of these as well, with the TH base. (and the accompanying socket) The filament shows continuity - but I haven't had the guts to put it on a variac yet! I'll have to set mine up and try it out. Thanks, as always Fran, for a great video...
A thing I keep on noticing about the filament is it's so fine that it responds to even the slightest vibration as well, which of course makes photographing it even harder.
not to mention making them ridiculously fragile too! Carbon filaments hate shock and vibration even more than tungsten does, and they blow quite rapidly!!
Before people start lamenting about how things were “made to last” back then, consider that these lamps were very inefficient (watts/lumen). Even compared to later day incandescent. The more robust the filament the more it acts like a resistor instead of a light source. Edit: *instead of a visible light source.
The fundamental misapprehension here is that anything was made to last. Nobody ever considers that hundreds of thousands of these were manufactured, and very few samples have lasted until today. These were built to be sold to people who wanted to adopt a new technology the provided light superior to candles.
I think they’re also generally under driven. Put more voltage to it to get full power and it likely wouldn’t last nearly as long. Even modern incandescent bulbs will last a lot longer at lower power levels.
That's beautiful. Looks like a neon tube. One minor thing, you went a long way round to work out the resistance of the fillament, it's just Volts divided by Amps. Sorry, it's just the more maths you use, the more errors can be introduced.
Surely this carbon lamp filament is essentially purely resistive at 60Hz, so a simple application of Ohms Law using rms currents and voltages would yield the resistance? But it's certainly a "cool" light bulb!
Incandescent lamps have non-linear resistive curves, relative to resistance v temperature. Most tungsten filaments have positive differential resistance, while this carbon tube filament has negative differential resistance. The latter baffles physicists to this day. The threshold for emitting light is much lower with carbon, and intuitively seems to point in the direction of higher efficiency. A japanese company is trying to make bulbs with carbon nanotubes, and expect production in next few years.
I have several bulbs I took out of service from a hydroelectric plant built in 1894. The bulbs were used to sync the generators to the bus. The all still operate.
That is a great shot of the bulb and the calculator at 5:10 : one antique being used to check out another antique. I still have both of my Texas Instruments calculators from college. The other 'icon' of that era was the Hp 35 scientific calculator. Engineering students carried them on their belts like sixshooters. No laptops or tablets then (except 'paper' tablets). A hard drive was the commute to school. BTW, an Hp 35 cost $350 in 1973. And that is 1970s dollars. That would be at least $1-2000 today. You didn't want to drop the thing for sure.
My reading lamp is a 40's era lamp with a 1920's or earlier carbon filament bulb in it, has that shiny sheen to it also, i run it at 95 volts. i believe it is also a 100v bulb love these bulbs so much
I used to think that the Centennial Bulb was defective. I knew that it was a Carbon Filament, but it was so dim and red that I presumed it was anomalously thicker than designed. Nobody told me that others were also still operational in the world. I think that is super k-neat-oh, just a beautiful artifact. Thanks.
The sound of those Ti keys is taking me straight back to my maths class at school in the late 70's. Why don't calculators have the feel & sound of keys like that anymore? Oh! The lightbulb? Just sublime! Like the end credits music. That's a smooth vibe with a capital SMOO!
Your Shelby bulb is a thing of absolute beauty! I have several antique bulbs as well, and while I do not have a Variac (yet), I do use these bulbs on a dimmer switch very carefully, and only on rare occasion. Thanks for showing us this beautiful piece of electrical history.
This has got to be one of your coolest videos. I worked in the electric utility industry for 39 years. I was always amazed at the components that were still in service operating reliably even though manufactured many years ago. Thanks Fran.
I seen the title and hoped you would mention that Fire Station. I remember seeing a documentary about it and when they moved the fire department they were super worried the bulb wouldn't turn on again in the new place. It turned on in the new location, no problems!
Fran! Buy a CPL (Circular Polarizer) filter for your lens. It lets you reduce/remove reflections from glass and other shiny surfaces - they're abundant, cheap and really cool/fun to use - seeing the world without light reflections on foliage and windows or glass cabinets is an interesting experience. Would enable you to film this type of stuff better.
Baltimore Museum of Industry had (by their online catalog, it appears only a few specimens remain) a large collection of antique bulbs, it was a fascinating exhibit to look at. Lovely to see this old Shelby being brought to life.
I worked in the fire station where the centennial bulb is housed. It is very well care for and if someone didn't point it out, you wouldn't even know it was there. We just knew that we had to be careful to not throw anything across the apparatus floor for fear of breaking it if it went too high.
Seeing your TI 30 reminded me of mine. Walking to a high school math test, dropped it. Down a flight of stairs. I've been shattered ever since. 1978, when I was 16. Used a calculator from a magazine subscription until I could afford a TI 35 which was horrid.
I have a similar bulb which has a lever on the side connected with cotton string. Sort of a Bright Dim Switch. There are 2 filaments, each with 2 turns. The dim one has loops about 3/8" dia and the Bright has loops about the diameter of a nickle. It still works. I have it inside a clear glass lens Lantern after removing the wick.
The way that filament harmonically bounces around in there it's a wonder that it lasts that long that's a whole lot of movement for a little bit of movement on the outside.... Very cool bulb... Fran.. you rock....
About 100 miles west of where I live is Mangum, OK. In their fire station is the Mangum Light. Another of the oldest continually operating lamps in existence.
I got a couple of antique carbon filament bulbs. They're probably not nearly as old, given they have regular Edison bases, but they still look really pretty in an antique lamp. Holy crap they get hot though!
The logo on Ms. Fran's shirt... Why is it so familiar? I would swear I've seen it somewhere else.... Really. Anybody? Excellent, calming content, please continue.
Thanks for properly dimming the lamp before killing power to it. It's a subtle thing that might be missed on those unfamiliar with incandescent lamps -- as you well know, heating and cooling the filament exerts mechanical stresses on the filament. It wasn't a big deal to put this on a wall switch back in the day, as it would have been, when one could wander down to the store and buy another if it burnt out. Decidedly NOT the case now.
Very illuminating, thank you. If I was doing that test, would have found it hard to resist the temptation to crank it up to full voltage to get an idea how these looked back in the day 😀. I still prefer the temperature of the old tungsten and halogen lamps compared to modern CFLs and LEDs.
The shiny grey filament, along with the small change in resistance with temperature, implies it's a "carburized" filament. These were made by heating carbon filaments in a hydrocarbon atmosphere (sometimes ordinary gasoline).
I hope LED technology keeps getting better, to the point it can completely emulate the type of light these put out. It's so calming! Though I tend to prefer warmer light in general. Nothing over 3000K for most home lighting.
Hi Fran. I just love the old school calculator. I had one for Christmas when I was young back in 79. It was the most amazing thing ever! Love your video's, best regards.
I just discovered your videos about 6 months ago and am astounded at how you have explained many of the electronic devices I have wondered about. I'm as old as dirt and remember and had one of the first transistor radios, one transistor. You are a treasure trove of information and a treasure to watch and learn. My sincerest thanks.
Thanks for taking the chance and powering that up to show all of us. That really does look amazing (more so at the lower voltage I think). The initial heating up of the filament is probably more risky that actually having it on after that. I know if I ever were to get one of these old bulbs, I'd probably set it up to run at low voltage constantly and just enjoy it while it lasted which would likely be for a very long time.
What a highlight to my day to see you talking about this bulb! I don't know if you've seen my video about re-creating a carbon filament lightbulb, but I did a solid few years of research and experimentation to make it happen. Quite an obsession for me. The carbon lightbulb is an invention that's right out of an era where the technology is such that I can wrap my mind around it. After the early 1900's technology starts getting over my head fast. To answer what the filament is made from, it's almost certainly extruded from a mixture of graphite or carbon black paste, bound together with nitrocellulose or a similar organic substance, and carbonized in place already pre-attached to the leading wires of the lightbulb. A glob of carbon paste is used to stick the filament to the metal wires before carbonizing, which gives the delicate carbon a solid physical and electrical connection (a hard thing to achieve between the mechanically dissimilar materials). Besides extruded filaments, the only other options commonly used were either paper or bamboo. It's pretty easy to identify a paper filament, though bamboo can look a lot like an extrusion to the naked eye, complicated by the fact that bamboo filaments were smeared with a carbon paste which would look identical from the outside to an extrusion. You may need to snap a filament and look for evidence of wood grain in the center under a microscope to be absolutely sure. One last interesting thing that was done to improve the life of filaments was to fire them up for the first time in an extremely hydrocarbon rich atmosphere before the bulb was blown over the outside. This caused the hydrocarbons to deposit and carbonize on the surface of the filament, filling any voids and imperfections. In areas where the filament was too narrow it would heat up faster causing more carbon to deposit and even out the difference. Really brilliant solution to improve consistency. Love seeing this bulb in action. I haven't dared to fire up the two carbon bulbs I purchased during my re-creation process.
I found a huge treasure trove of old bulbs in New Zealand in the early 80s. These were in an old movie theater near Wellington the capital city. Most of these were from the thirties and were colored glass for the theater mood lighting that was standard in the old days. A few were older and had the pointed Pontil end on top, and clear glass. Don't know how many were really old, but there were hundreds and they were rare even then. No idea what happened to them all, but I sold a lot to a curiousty shop in Cuba street. I still have a lot of old fittings and early lamps and stuff. Your comment is really interesting. Cheers.
I was going to ask Fran if she is sure this is a carbon filament bulb, and not a metal filament one, because the filament attachement point to the incoming leads looks like welding. They can be a blob of carbon paste, though. Although the one on the right side feels too thin to me for being a carbon blob that still holds it together after 100+ years.
@@mrnmrn1 Yes, its definitely a carbon filament. The carbon putty used to glue the filament to the leads becomes one unified piece of graphite, one piece with the filament when it's fired. It's a great way to join metal to carbon. For metal filaments welding was hardly if ever used because it's easier to clamp. Those didn't come until several decades later though, when forming thin tungsten wire became possible.
paper filaments? how in the world did they not burn up? I've heard of bamboo filaments before but cant wrap my head around that either, how would they produce such a thing string of bamboo?
@@SpydersByte They were carbonized, basically turned into charcoal then heated further turning the charcoal into graphite. In my video recreating the filaments I used both cotton string and paper with success. Some of the best advances to filament technology came from a guy called Lewis Latimer who invented a reliable way to mass produce paper filaments, though bamboo was still I think dominant for the early years, then extruded filaments probably using a variation of Latimer's process to carbonize them.
The original Shelby bulb was first manufactured in the 1890s. There is one bulb which is currently lit at fire station number 6 in Livermore, CA. The bulb has been on for over 1,000,000 hours and is in The Guinness World Record book for its long life. Great bulb Fran : )
You'd be lucky to get 1/1000 that life out of a modern incandescent.
@@deadfreightwest5956
This is absolutely true, however a modern bulb also puts out significantly greater light at lower consumption.
But ends up being a disposable item.
What's been very disappointing to me is the supposed extreme long life of LED bulbs and quite frankly most of them end up failing sooner than incandescent did. It's not usually the LED itself that fails it's always the crappy electronics that drive it or poor solder connections.
Fortunately they've gotten cheap enough at this point but it kind of doesn't matter financially but it still bothers me that it's wasteful and stuff gets tossed in a landfill that should still be operating.
@@kens97sto171 Yep. I have several older LED bulbs built with super heavy heat sinks and they still work. The newer LED bulbs fail less than a year.
@@Darkk6969
I've had a little better luck than that with the cheaper LED bulbs, at least the ones you get at home depot that replace incandescent bulbs with your standard light bulb.
where I've had terrible luck with LEDs tend to be things like stuff off of Amazon or ebay .
Inexpensive solar outdoor lights some of them not that inexpensive.
Inexpensive LED flashlights. Things like that
and very rarely is it actually the LED that fails it's usually a crappy solder joint or some secondary electronic component like a capacitor etc or in the case of solar lights the battery craps out.
Cant believe anything CA government says. Use to ride my motorcycle up in that there. There is a top secret rocket base hidden back in there. I use to see rockets fired at night every so often so i went looking,
About 15 years ago they were renovating a high school in my area and during the high school renovation I managed to acquire about eight of those exact Ti calculators....I acquired them out of a dumpster which I thought was pretty sad but they all worked....
@@awesomeferret
I'm not sure that's even true but how good do you think a modern plastic device is going to feel 50 years from now? Oh yeah it won't still be around because it'll long ago have been in the landfill.
@Blu Crystl The TI30 was never expensive.
The old factory of the Shelby Lightbulb company is now a surplus store that I frequent. I've been told that upstairs in the old factory building is still some of the equipment they used to make the light bulbs.
GET. SOME. PHOTOS. GIVE THEM. TO. FRAN.
That sounds super cool. Sounds like a neat thing to see and I don't see why they would have an issue with it if you frequent the store. Fran would probably think its super cool too.
Cool channel I gave you a sub. I think its neat that Fran gets so many creators that frequent her channel. She really is one of the greats on here.
History should be preserved before it disappears forever.
Puts me in mind of "The lightbulb conspiracy!" Very interesting documentary!
Turns out 1000 hours is a good efficiency-life compromise for a general service lamp...
@@bigjd2k Yup, take your 120v 1,000h bulb and run it at 110v and you'll get 3,000h out of it. Run it at 100v and get 10,000h but also a 27% reduction in efficiency. So for a bulb that costs 1$ to buy but uses 10x as much dollars worth of electricity during its life I think it's better for them to be as efficient as possible.
@@bigjd2k so if a bulb reaches 1000 hours it burns out ?
@@matthewgregory8218 I think he means "on average", not every specific bulb. Mean time before failure=MTBF.
Love that filament! There’s art there as well as function
If you got a polarizer filter in front of the lens maybe you could eliminate some of the reflections
Or try a back light arrangement.
A Poloroid® filter on the camera lens would only help with reflections if the light source causing the reflections is also polarised, and it’s at the right angle.
Remarkable difference between carbon and tungsten filament lightbulbs: a tungsten lamp will always break when you switch it on, a carbon lamp will break while it is on and on operating temperature.
Positive vs negative temp coefficient.
@Damedane
Define best. ;)
@@NiHaoMike64 😂✌🏼
Ahh. I thought she made a mistake when she said the resistance drops when it's hotter. That's something new I learned today. Thank you.
So I guess when one of these fails, its almost like an un-ballasted HID lamp - In that it gets hotter, draws more current and has a runaway effect.
I can imagine that this made the carbon filament lamps much more difficult to design.
Tungsten has a limited capability to regulate itself to an extent.
robber576 This is interesting, I always thought the initial surge of power was the most likely time to cause any bulb to fail.
Sometimes tungsten fails during operation, and it can be quite fun. I've seen one example up close about 10 years ago. The filament opened at one end, but continued to operate. The only thing I realised was a weak, about 400Hz tone coming from the lamp. When I went closer I could see a small, bright blue arc where the filament broke. The arc held together the filament for about 10-20 minutes!
It is a work of Art.
It reminds me of a story my grandfather told me when I was about 11 or 12;
He was in Montreal, during the McGill university riots.
He was standing beside a Surete Du Quebec officer, watching the fires and students smashing a large computer.
A vacuum tube, flew or rolled up to my grandfather's feet, and he bent over, picked it up, and asked the cop if he could have it as a souvenir.
"You can `ave, is garbage now"
He labelled it and kept in a pill bottle.
I inherited it after he died.
He also while in Quebec, visited one of the Mines there, and told me it was opened in
1800 something, and that "most" of the original (Carbon Filament) bulbs, were still lit, working, and never switched off.
"They've been lit for (nearly or definitely) 100 years".
I have one very similar to what was in the Mine. It was never used, but unfortunately, the tip was broken, so it's just a memento.
Neat bulb. Back when artists and craftspeople made them, before mass production.
they are still hand made, small batch by glass blowers, sometimes for movie industry, or individuals, very cool to see done.
@@randymack1782 The bulbs are made, but they put tungsten filaments in them and run them at lower voltage to replicate the carbon look. I spoke to the curator of the Menlo park exhibit at greenfield village for some time about where their replica bulbs were made and how they work. As far as I know nobody is still making real carbon filament bulbs besides people like myself doing it just as a hobby to explore the science.
People were terrified of light bulbs and electricity took over 20 yrs for it to be accepted Gramps wood not put in power till after he died and dad put in power in 1946
10 thumbs down from the LED industry.
Haters are hard to understand. I don't get how this got any downs. Do they hate electrons? Digital Multi Meters? Filaments? It can't be photons, can it?
It must be Variacs™ that are hated !
@@therugburnz you know i have thought the same thing many times on all kinds of videos and i think i have come up with an answer as i, myself every now and then accidentally hit the dislike on my touch devices. I want to believe I've noticed it every time and undone it. But its very possible I've missed a few and left some dislikes behind. I assume the same things happen to the like button so i think the ratio of likes/dislikes is the only thing to go by.
😁😆
Why? She's using a retro TI calculator with led digits!
You're not getting it. If you had vested interests in the LED market you'd give the incandescent world a ribbing.😁
I have strings of series-wired 15 Volt carbon filament Christmas lights. I believe they are from the early 1900s. All of them still work today, and there are boxes of spares. They get hot like crazy, especially the blue and red, but I guess this would be considered 'safer' than candles !
Here is a video showing the 100 year old Christmas lights: th-cam.com/video/Vyx_nptgup0/w-d-xo.html
Well that's brightened up my evening.
When I was a kid I remember my dad having an old bulb with an elephant in it.
These bulbs are to cool! I was lucky enough to acquire a working Shelby bulb too “now under glass.” They are a neat and important part of lighting history.
I love the glass envelope shape, it's just beautiful.
Older ones and prototypes had a. Glass tail on top when they were blown by hand
Fantastic! The oldest bulb in my collection is only about 75 years old, and I know a guy who has a bulb that was saved from WW1, from the British trenches in France. It's dated as 1915, both on the glass bulb, and on the carton. I wish I could remember the manufacturer, but I'd only be guessing now. I did once hold that bulb, and it was a strange feeling, holding a fragile piece of history. I asked him "How much" but it wasn't for sale at any price. It was his dad's before him, and he took possession of the bulb along with his dad's electrical repair shop when the old man retired. The bulb lived on a shelf in the shop along with a myriad more vintage electrical artefacts. I was able to buy a few of the lesser items from his collection, but nothing like this little lamp of yours.
It's hard to fathom that electric lighting goes back so far, and that candles and oil lamps remained staples of domestic and commercial lighting for so long after. Indeed, some isolated places not far from me didn't even see an electric light until the early 1980's!
I've seen the Centennial bulb, and amazing as it is, it is quite seriously under-run and will probably outlast the planet! It is safely tucked away in a quiet corner of the fire station where no one and nothing, short of an earthquake, will ever disturb it. It is well looked after!
That bulb 💡 is gorgeous, but that calculator is amazing!!! 😃
R=U/I for some simpler calculation of resistance. No need to go for the power first.
Love to see some interesting old "electronics".
60V/0.132A=455Ω
Back in the early 60’s, my uncle had a multi-filament bulb similar to this on his front porch. He bragged that it would last a very long time.
OMG total flashback. I had one of those TI-30s when they were brand new
Hah I thought you were going to say you had one of those light bulbs when it was brand new.
bloody posh kids :)
Me too. I loved the book that came with it. "The great international math on keys book." It's still around at my parent's house lol.
@rogerwilco99 I understood how to use a slide rule for about two weeks in high school in 1973, then promptly forgot everything when the powers that be decided to allow calculators in class. My first was the SR-10, and doing squares and square roots was endlessly entertaining! My early TIs from high school and college are long gone, but I have an HP-12C in (almost) daily use since 1984...those things are built like tanks!
Hi Fran, am a light bulb collector of the incandescent type. What a beautiful Mushroom Shaped light bulb. I do have a lot of these from Osram. "I bought these from ebay and got a good collection of Mushroom Opal Light bulbs which are milky white in colour and beautiful when lit." They are quite pleasing to the eyes as well. A nice soft white light. Thanks for showing us your video it was very interesting to watch.
Love your obvious pleasure in this little rarity. I share your pleasure in various vintage bulbs big and small in my collection. It's amazing that some can see beauty in what others perceive as old junk.
I love the ancient variac and the TI-30 calculator.
LED bulbs exist today at your local big box hardware store that provide the aesthetics of these bulbs, but with a much higher efficiency. I have one over my sink. it's quite nice.
I have one in the porch lamp on my house here in the UK, which was built in 1899. (The lamp itself is an original 1940s cast aluminium swan-necked corner fitting by Coughtrie of Glasgow, who still make lighting today, including a modern version of my lamp). It has a lovely teardrop-shaped clear glass shade full of little wobbles and imperfections. The bulb I bought for it is LED but has the little nipple on the top and puts out a lovely warm glow that's a nice contrast to the modern cold while LED street lighting recently installed in my neihhbourhood.
My heart was in my mouth as you turned the voltage up... what a beautiful artifact, Fran.
Thank you for sharing:)
Didn't realize the extra streaks of light were reflections until you pointed it out. Thanks for sharing
Thanks Fran. You light up our lives! Your curiosity and appreciation for often legacy technology is infectious. And your laugh/chuckle is the most endearing ever. 🥰 Lovin it in Canada! 🇨🇦
Not limited to Canada 🇩🇪 🏳️🌈☺
I used to have a TI-30. I bought it for high school chemistry back in 1981. It was my first scientific calculator.
Fran, I just have to say that I absolutely love your voice. At the start of your videos when you say "hi it's Fran in the Franlab", it never fails to bring a smile to my face. It's comforting, almost like singing or something. Anyways just wanted to tell you how much I appreciate your videos. I'm always enthralled by your content.
Me too. In my case Fran, your voice is also a lot like my ex so you also bring a smile to my face for that. Brings back good memories.
I love your light bulb, and that you also love your light bulb! Not enough true nerds in the world!
That is extremely cool! I happen to have one of these as well, with the TH base. (and the accompanying socket) The filament shows continuity - but I haven't had the guts to put it on a variac yet! I'll have to set mine up and try it out. Thanks, as always Fran, for a great video...
A thing I keep on noticing about the filament is it's so fine that it responds to even the slightest vibration as well, which of course makes photographing it even harder.
not to mention making them ridiculously fragile too! Carbon filaments hate shock and vibration even more than tungsten does, and they blow quite rapidly!!
Before people start lamenting about how things were “made to last” back then, consider that these lamps were very inefficient (watts/lumen). Even compared to later day incandescent. The more robust the filament the more it acts like a resistor instead of a light source.
Edit: *instead of a visible light source.
Yea... No one would use those bulbs today, because they are just so crappy in terms of light production... no matter if it would last forever.
The fundamental misapprehension here is that anything was made to last. Nobody ever considers that hundreds of thousands of these were manufactured, and very few samples have lasted until today. These were built to be sold to people who wanted to adopt a new technology the provided light superior to candles.
I think they’re also generally under driven. Put more voltage to it to get full power and it likely wouldn’t last nearly as long. Even modern incandescent bulbs will last a lot longer at lower power levels.
@@aivansama6265 - But you could hold a candle to them!
@@deadfreightwest5956 I think the candle might still win out
That's beautiful. Looks like a neon tube. One minor thing, you went a long way round to work out the resistance of the fillament, it's just Volts divided by Amps. Sorry, it's just the more maths you use, the more errors can be introduced.
What's the fun in that?
@@FranLab Ha ha, good point.
Surely this carbon lamp filament is essentially purely resistive at 60Hz, so a simple application of Ohms Law using rms currents and voltages would yield the resistance? But it's certainly a "cool" light bulb!
Incandescent lamps have non-linear resistive curves, relative to resistance v temperature. Most tungsten filaments have positive differential resistance, while this carbon tube filament has negative differential resistance. The latter baffles physicists to this day. The threshold for emitting light is much lower with carbon, and intuitively seems to point in the direction of higher efficiency. A japanese company is trying to make bulbs with carbon nanotubes, and expect production in next few years.
Looks like the idea light bulb💡 I imagine popping up over your head watching your videos😉
I have two TI SR-40 calculators similar to yours. I always loved the LED numbers.
I love this woman for her love of electrical engineering.
I have several bulbs I took out of service from a hydroelectric plant built in 1894. The bulbs were used to sync the generators to the bus. The all still operate.
What a cool thing to own. Very neat. Thanks for sharing your bulb with us.
That is a great shot of the bulb and the calculator at 5:10 : one antique being used to check out another antique. I still have both of my Texas Instruments calculators from college. The other 'icon' of that era was the Hp 35 scientific calculator. Engineering students carried them on their belts like sixshooters. No laptops or tablets then (except 'paper' tablets). A hard drive was the commute to school. BTW, an Hp 35 cost $350 in 1973. And that is 1970s dollars. That would be at least $1-2000 today. You didn't want to drop the thing for sure.
My reading lamp is a 40's era lamp with a 1920's or earlier carbon filament bulb in it, has that shiny sheen to it also, i run it at 95 volts. i believe it is also a 100v bulb love these bulbs so much
Love that TI30 calculator. I used one back in the 70's.
I used to think that the Centennial Bulb was defective. I knew that it was a Carbon Filament, but it was so dim and red that I presumed it was anomalously thicker than designed. Nobody told me that others were also still operational in the world. I think that is super k-neat-oh, just a beautiful artifact. Thanks.
Thank you for lighting up our life Miss Fran . . . . from the bench . . . . in your Fran Lab.
I love the reflections of the filament in the bulb. Excellent thing to collect
The sound of those Ti keys is taking me straight back to my maths class at school in the late 70's.
Why don't calculators have the feel & sound of keys like that anymore?
Oh! The lightbulb? Just sublime! Like the end credits music. That's a smooth vibe with a capital SMOO!
you should be a professor. You are one of the best producers and teachers on TH-cam. I love you Fran!
That looped filament is really interesting and Gorgeous. 100+ years. Wow.
Your Shelby bulb is a thing of absolute beauty! I have several antique bulbs as well, and while I do not have a Variac (yet), I do use these bulbs on a dimmer switch very carefully, and only on rare occasion. Thanks for showing us this beautiful piece of electrical history.
This has got to be one of your coolest videos. I worked in the electric utility industry for 39 years. I was always amazed at the components that were still in service operating reliably even though manufactured many years ago. Thanks Fran.
those old carbon lamps last for a long time. i've got a couple I use in my bedroom for warm cosy lighting :)
Your happiness is contagious and I hope to see many more fun Videos.
Why is it that light blubs are so attractive.
I seen the title and hoped you would mention that Fire Station.
I remember seeing a documentary about it and when they moved the fire department they were super worried the bulb wouldn't turn on again in the new place. It turned on in the new location, no problems!
Oh my gosh.! I have not seen a Texas Instruments calculator like that since I was 11 years old in 1979!
Beautiful! Thanks Fran!
Nice, the oldest bulb I own is from the 1920s, rated 16 candle power. I use it in my study.
Fran's got a glow on!
Found out about this bulb awhile ago. An explanation is so great to see.
Using an old calculator is fabulous. That's style.
Fran! Buy a CPL (Circular Polarizer) filter for your lens. It lets you reduce/remove reflections from glass and other shiny surfaces - they're abundant, cheap and really cool/fun to use - seeing the world without light reflections on foliage and windows or glass cabinets is an interesting experience. Would enable you to film this type of stuff better.
Baltimore Museum of Industry had (by their online catalog, it appears only a few specimens remain) a large collection of antique bulbs, it was a fascinating exhibit to look at. Lovely to see this old Shelby being brought to life.
the blues jam at the end was sick :D
You are brighter than any bulb. 💡❤ 💡
Awesome video!
The filament in that Shelby bulb look like the filament we have in flash bulb for photo back in the days and the flash bulb was single use ! 💡⚡
Was this bulb made to run on nice safe direct current or on that newfangled alternating current that kills elephants?
It runs on plastic straws and turtle oil
A Texas Instruments TI 30 from the late 1970’s - a class act right there.
Thanks for showing us this. Early production light bulbs are fascinating. I've read about them, but never seen one close up before.
I hafta say, I dig that understated, matter-of-fact outro theme.
Wow i can't believe that lamp lasted 120 years, and still running 🕯️💡
Because it's not been used or hardly had any use.
Interesting that the vacuum was still there
I worked in the fire station where the centennial bulb is housed. It is very well care for and if someone didn't point it out, you wouldn't even know it was there. We just knew that we had to be careful to not throw anything across the apparatus floor for fear of breaking it if it went too high.
Seeing your TI 30 reminded me of mine. Walking to a high school math test, dropped it. Down a flight of stairs. I've been shattered ever since. 1978, when I was 16. Used a calculator from a magazine subscription until I could afford a TI 35 which was horrid.
Pretty cool lamp, and a snazzy variac too.
I have a similar bulb which has a lever on the side connected with cotton string. Sort of a Bright Dim Switch.
There are 2 filaments, each with 2 turns. The dim one has loops about 3/8" dia and the Bright has loops about the diameter of a nickle. It still works. I have it inside a clear glass lens Lantern after removing the wick.
The way that filament harmonically bounces around in there it's a wonder that it lasts that long that's a whole lot of movement for a little bit of movement on the outside.... Very cool bulb... Fran.. you rock....
Also appreciated the TI30 calculator still kicking. (i have a fully functional Curta mechanical calculator- which I dust off from time to time)
About 100 miles west of where I live is Mangum, OK. In their fire station is the Mangum Light. Another of the oldest continually operating lamps in existence.
I got a couple of antique carbon filament bulbs. They're probably not nearly as old, given they have regular Edison bases, but they still look really pretty in an antique lamp. Holy crap they get hot though!
The logo on Ms. Fran's shirt... Why is it so familiar? I would swear I've seen it somewhere else.... Really. Anybody?
Excellent, calming content, please continue.
Thank you for the rare opportunity to see such a unique bulb.
Thanks for properly dimming the lamp before killing power to it. It's a subtle thing that might be missed on those unfamiliar with incandescent lamps -- as you well know, heating and cooling the filament exerts mechanical stresses on the filament. It wasn't a big deal to put this on a wall switch back in the day, as it would have been, when one could wander down to the store and buy another if it burnt out. Decidedly NOT the case now.
Fran, if you use a polarized filter on your camera lens we should be able to peer through the glass better. 😊👍🏻
Cool bit of history, and it still holds a vacuum and lights up after all these years!
Thanks, Fran! This is lovely.
"This little light of Fran's...
She's gonna let it shiiine..."
Beautiful filaments...
Very illuminating, thank you.
If I was doing that test, would have found it hard to resist the temptation to crank it up to full voltage to get an idea how these looked back in the day 😀. I still prefer the temperature of the old tungsten and halogen lamps compared to modern CFLs and LEDs.
Very cool old bulb, and that Ti30, late 70's! I remember having a Ti55 back in high school! That both are still working and usable is really cool!
The shiny grey filament, along with the small change in resistance with temperature, implies it's a "carburized" filament. These were made by heating carbon filaments in a hydrocarbon atmosphere (sometimes ordinary gasoline).
Fran, you are a beacon of light...
I hope LED technology keeps getting better, to the point it can completely emulate the type of light these put out. It's so calming! Though I tend to prefer warmer light in general. Nothing over 3000K for most home lighting.
So pretty! Thank you so much for sharing the joy of this beattiful ancient glow with us.
Finally! A good video about the Shelby bulb!
Hi Fran. I just love the old school calculator. I had one for Christmas when I was young back in 79. It was the most amazing thing ever! Love your video's, best regards.
I just discovered your videos about 6 months ago and am astounded at how you have explained many of the electronic devices I have wondered about. I'm as old as dirt and remember and had one of the first transistor radios, one transistor. You are a treasure trove of information and a treasure to watch and learn. My sincerest thanks.
Thank you so much for sharing my kids loved this videos!
I've loved watching your channel since 2014 Fran!! :D Love the new vid about disposable consumption
Thanks for taking the chance and powering that up to show all of us. That really does look amazing (more so at the lower voltage I think). The initial heating up of the filament is probably more risky that actually having it on after that. I know if I ever were to get one of these old bulbs, I'd probably set it up to run at low voltage constantly and just enjoy it while it lasted which would likely be for a very long time.
Wow! Fran, I was holding my breath when you ramped up the variac. What a totally cool and way beautiful light bulb! I'm jealous!
Your channel is a gem. Don't know how I didn't find it for so long.
Thank you for bringing the filament gradually down to zero, I didn't have to have an anxiety attack :-)