Interesting Experiments With Fluorescent Tubes

[Music] ah yes the humble fluorescent tube one of my favorite lighting sources and certainly one of the most popular during the mid 20th century but sadly it's all being phased out with modern led stuff which i'm not so keen on fortunately i've saved some of the most unusual and rare fluorescent tubes so we can all enjoy those at a later date but today i think we need to do some weird and wacky experiments with fluorescent tubes that perhaps you haven't seen before which will obviously make things more interesting so let's crack on and have a little bit of fun shall we old bc ones i've put in some kopecks just to protect them they are t12 size most have got brass ends they don't see these anymore that's the gold one there so i like that all sorts of colors green blue pink gold reflector the uh much older ones of course have the brass caps the aluminium came in a bit later but they are nice it's nice to have a couple of samples of each then we've got some smaller ones all different colors and these are quite nice so luckily i've kept a few which is a nice thing to do these are a blast from the past look at that don't see them anymore the old green ones for the fax machines put a window in it proper old tail another old one there little tiny 10 watt bc that well i don't want to boil the bollocks off yeah but i've got to do all this to justify smashing a couple up in a minute so bear with us i know you all know how these work but i will demonstrate because it's out and it might be useful so on the left hand side of the tube we've got a neutral going straight to it the life goes through the ballast or into the ballast at the top center comes out of the ballast and goes in the right hand side of the tube so there is now 240 volts at each end of that tube but nothing's happening the voltage is not traveling from one end of the tube to the other because we need something to happen before that can occur and what we need is thermionic emission that we get achieved simply by joining these two wires together now a current goes through these two heaters at the end we have emission we now open the circuit and it comes on simple as that the ballast limits that current let's have a look at the starter in a bit more detail this starter really is an old-fashioned one it's almost got a lot of light bulb based on it but it has sbc base so there's two contacts there inside that are open and there's a tiny amount of gas in there probably argon and when we get a small current discharge between that gap the bi-metal warms up and closes that gap then of course when all the currents too busy going through the fluorescent tube it no longer wants to go through the starter so the voltage at the starter becomes very low and it's out of use until the tube is turned off so let's have a look at this when it fires up because it's quite nice so open and you see the gap open wider still open just close this temporarily you see it widening up so straight forward this is the more standard type of starter obviously you can get electronic ones as well let's open this one up you can see the bi-metal there slowly widening that gap let's do it again the gap widens up very very simple right that's almost a boring bit done let's open one up carefully if you've got headphones on now's the time to reach for that volume button because oh there i popped it let's have a look at the guts a bit this is one of the ends now you can see we've got this little heater and you definitely don't want to put 240 volt on that heater because your pocket only needs a few volts there it is you'll see some white stuff on there i probably can't focus much more than that some of these have barium strontium or different calciums on there just so when this gets hot it helps with that thermionic emission just to get some atoms going and then we get conduction down the rest of the tube so it probably only needs you know a few volts on that that looks like a coiled coil this tube here looks quite ordinary one in but it's a half coated one very unusual so we'll be able to see what's going on let's turn this on shall we this is this half coated tube just about to turn it on so you'll see the heater come on just very briefly maybe a bit of a delay on this one just so you can see it then the starter will go off open circuit and the current will go straight through the tube let's turn it on heater on there we are so this looks like uv is coming through this glass but it's not because this is glass and not quartz the uv doesn't make it through the glass so it is purely inside so with this coating these phosphors obviously when the uv hits this phosphor it illuminates if this was quartz the uv would come straight through it and it'll be quite hazardous but this one is safe so you can see the actual point there where the emissions take in place tiny little hot spot that's a quite rare tube that one now what we're going to do is play with some uv with a quartz tube and put some phosphor on it shall we i think so this tube is made of quartz so it will emit uv this one's a t10 so let's turn it on there's you can see the uh phosphor there lighting up so if i get bit of this tube put it on there you can see that lighten up and i can smell ozone so we're not going to do too much of this there it is that's how they work simple just for fun on this one i've slid the t12 tube what's left of it over the t10 so now when we turn it on we've got more visible light than uv still not good though that's exactly how the fluorescent tube works ultraviolet light hits the phosphors and gives us useful visible light what a wonderful light source that was so from the smallest which is like one of these little cold cathode things up to the biggest which is some of my favorites the gigantic t-17 power groove these are fat with a capital f they are huge this is t12 this is t17 there is a big difference don't really see these anymore the old power groove because they do them eight foot long this one's a relatively small one four foot good old usa right now then i'm now going to try and take this end cap off without breaking it and have some fun so very carefully remove this without busting the tube just get those pins brutal dislodged those things sometimes one pin there's the cap off let's just this last little pin there that holding things up let's get that in there there we go so we've got the end off without any damage we can still test it with this if we uh still light up look at that right so this little bit here is where it's sealed off when the air is drawn out and i'm deliberately gonna break that now so we can see the air go rushing in barely get that to focus so these are my special pliers which i get on here once i break this you'll hear it you ready [Music] so what happened there the air went rushing in so violently it pulled that phosphor off the edge of the glass so we know it was a vacuum because it pulled in rather than blew out naturally it's not going to work at this precise time but get an idea of how much of a vacuum that was this is where it gets interesting and the question is how much of that tube was a vacuum and how much was gas so we've discovered that these tubes are in fact quite a hard vacuum as you know when you drop it on the floor it's quite a satisfying pump especially in slow motion like this [Music] when you overload the things they're not that exciting they burn out quite quickly maybe a little bit brighter than they should be but nothing fantastic but the best result is of course sticking one straight on a capacitor and dumping maybe a thousand damps for it or more at 5000 volts of course it doesn't last long at all so we're looking at this tube that now has air in it because we broke the seal so the question will be how much air was pulled out hopefully all of it but more importantly how much gas perhaps are gone as a buffer gas i think some of these t12s used argon and some of the t8s use krypton as a buffer gas just to get things going really it's a low pressure mercury discharge length because there is a tiny amount of mercury in there but the argon just helps it conduct a lower voltage and get things going and obviously these heaters down the bottom just get some thermionic emission from the mercury atoms and the argon just to get current to go through it so what do you reckon do you think all the air is extracted and then argon's injected to this point perhaps or halfway how much argon or buffer gas do you actually reckons in there any idea well i think we need to find out so i think what we should do is break this little nipple under water and then we'll see how far the water gets pulled up the tube and that will tell us how much of a vacuum it really was so obviously if it just fills up to there with water the rest of it was gas because it wouldn't be a vacuum anymore because the equilibrium obviously if it fills up to here then it's quite a hard vacuum and just a small amount of gas maybe it'll just fill up to here what do you reckon i know the answer and it's quite surprising should we have a look place your bets i'm now going to add some dye to this water just so we can see it going up that tube don't need too much just need a little bit of diet there that's let's have a go with this one then well obviously not too much gas in there almost a total vacuum right let's rotate this little bit get it under there there we go that's putting that up nicely turn well eight foot tube that wasn't bad was it look at that so that was all what was left that's going all the way up there top to bottom that's only about an inch from the top that's pretty good this is the disgusting modern equivalent of the 58 watt t8 oh god look at that yeah leds that's a swear word to failure let's have a quick look at this i'm gonna bust it badly because i don't like this here's the led tube it all looks good but you know there's one there a little bit dim two there a little bit dim oh dear they're not looking too good and as for this off it doesn't work at all silly electronics that's what that is i think we ought to uh force it to work what do you think some of this bit of that and some of that what a load of rubbish you'd never even notice that it was off that cover on would ya that rubbish that is once that diffuses on it you think oh yes that looks that looks all right apart from half of it not working yeah that's rubbish let's do something with it put it out of its misery all that nonsense to get a bit of light you know fluorescent light can last 30 years this ain't going to last three years rubbish anyway i've made the repair so turn it on and crank it right up until it pops we've now got it running on ac but sadly only half of that led strip is actually working so uh i think we'll just turn this up see what happens shall we oh now the other ones come alive unbelievable i can't believe that over vaulting that actually got the other one on not for long look how many of their busted that's unbelievable all going to be busted now in it you ready that's the end of that thing game over didn't take much today gentlemen and ladies thank you very much for watching the videos there will be plenty more where that comes from hopefully a little bit more interesting than that but that was one i wanted to get out of the way so as always thanks for your patience and i will see you soon it's these shirts that's what's making me so rigid i've got a little bit of a gut now these shirts are so tight i can't move it's like being in a cardboard box i have to move like this i've got to get some more shirts that's what the problem is so you know everything works it's just a bit tight too many pork pies see you later bye bye [Music] you

Channel: Photonicinduction

Views: 320,364

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Id: Cqi-l16gjSI

Length: 23min 29sec (1409 seconds)

Published: Thu Jul 15 2021