Thank you so much! I really appreciate that. I actually did teach at university for a while after finishing grad studies but ended up in the hi-tech industry for most of my career. I did enjoy the teaching part but truthfully would have gotten tired of it after teaching the same courses again and again. I still occasionally do stuff with a local university - usually judging their 4th year thesis projects or sponsoring/advising a particular project. For what its worth, many of my videos (including this one) are modified from material or labs in 2nd, 3rd, or 4th year Electrical Engineering of Physics courses or labs that I have either taken or taught or both. But what I try and do here is minimize or eliminate the science and math background that is usually needed to keep things accessible to a general audience, but still present things in a way that is sill meaningful and properly represents the (often more complicated) underlying theory.
Hello, do you have a business email or email to contact you. I would like to discuss about this system. I’m a student at a university with the same system and would like some assistance in troubleshooting. Thank you.
Thank you so much! Really appreciate being called a great teacher - what I am trying to do with this channel is present things is an understandable way that doesn't need the background one might normally need to understand them.
That's not an ideal test.. if you read the laser printing on the 14 gauge wire (before the NFPA gets ahold of it) will handle 250 amps at 240 volts. You're doing a dead short not a load test. Under a dead short the breaker will trip. Under load is where you see longevity of amperage/volts/VA/ and heat. You should redo the test with a 120 volt 40 amp load like a few motors.
The heating of the wire is from the voltage developed along the wire due to the current encountering the wire’s resistance, a few volts in this case. If the voltage between the wires was 120V (or 240V) with a load attached to the end of the wires, the same voltage drop of a few volts would be measurable along length of the wires for a given current and the heating would be the same. 120V times the current would be the power delivered to the load, different from the power that is dissipated in the wires which we are interested in. To keep this test simple and safe, there is no load (by shorting then end) and all we need is a few volts to create the desired current - and heating in the wires. See "OVERCURRENT TESTS FAQ" here ru-vid.comUgkxeilOfLJGy2ODslnBW0WFXUE580oHhFyP including why a current source like welder is used and a link to a UL test done in almost the same way.
@@ElectromagneticVideos I'm an electronics engineer. if the thickness of the wire was the culprit then 4kv Transformers would be as big as a car. they often use 40 gauge wire and not so discernible heat.
@@chuckholmes2075 Thats because we use HV to be able to reduce current and use thinner wire. Demo here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-prQssIL0VmA.html
Nice vid! Goes to show you that the old knob and tube I grew up with are relatively safe. An argument could be made that it is even safer than the current wire as you get much more convection cooling per wire.
Thanks! Yes - if used properly, you cant beat ceramic insulators and as you put it, convection cooled wire. Unfortunately though, it seems like many installation have been made unsafe over the years by covering the wire with blow in or other insulation, and also adding on to the existing circuits with improper connections and also overloading them.
You would think that the refraction of light would change its relative speed of light, thus changing the color of light like a prism. i guess that is what a rainbow is.
The reason for the rainbow effect is the index of refraction varies slightly with wavelength so one end of the spectrum is slowed/bent more than that the other. In the case of glass or water, index of refraction = slowing of speed - is large - 1.3 to 1.5 or more, so there is a lot of room for the speed change to vary. In air, which has a small index of refraction. , there is probably a wavelength dependant change, but would be so small - and the average bending is so small to start with - we would never normally notice it. The effect has plagued lens makers for centuries using different types of glass in a series of lenses to try and undo rainbow creation. Also in optical fibers where slight wavelength dependant speeds can distort signals being transmitted.
As a child when living on Long Island in New York, I once saw a Superior Mirage which manifested as the disk of the Sun setting twice. It was dusk, the Sun was out and setting. The disk past below the horizon and a short time later, the disk of the Sun reappeared above the horizon and set for a second time. I remember at the time that recognizing atmospheric refraction caused the effect.
That must have been really neat to see and obviously very memorable. So was it actually two suns for a while, or the sun re-appearing after setting the first time in repeating the sunset?
11:12 this part about measuring and compensating for the wobble reminds me of what we discussed in the comments of your mirage video, about measuring the amount of deflection on the laser over the toaster
Exactly!!!!!! You know, I should have mentioned haw mentioned that its the same thing that makes the stars twinkle and for more details see that video.
Yes - not sure if its a regional thing but from the comments maradge is more common than "my" way. I have lived all over so no idea where I picked up the mir-age variant.
You know I was debating on whether to put that in or not and in the end I didn't because I find it better to stick to one topic for RU-vid. Think of how either bulldozer or a military tank turns: the one track is made to go faster than the other and when that happens, the vehicle turns towards the slower side. Now instead of the bulldozer, think of light waves like water waves on the ocean. If the waves pass into air where say on the left is hot and thin and move faster. and on the right is cold and slow, the crest of waved between the left and right areas will bend towards the slow right side as the right cant keep up with the left. Hope that makes sense! maybe future video!
@@Schismarch I cant think of an easy hand-waving explanation for point-like particles. In quantum mechanics, the point where a photon is detected is based on probability - and that probability comes from a wave function that contains an amplitude which when squared = power = probability, and and complex exponential which in this case represents the wave nature of light. The wave function depends on the surroundings - thin air, thick air etc. The EM wave of wave theory is essentially the average of where gazillions of photons would end up from QM. In a situation like this, the real part of the of wave function essential;y maps to the EM wave. So the wave function is in a sense a probability wave (well not quite since its more like the square root of probability) rather than an E field. But like the E field wave, the "probability" wave speeds up in thinner air and bends accordingly. So once again we have different speeds bending an underlying wave. Why the probability wave cares about thick or thin air is another can of worms - it can be looked at as interference from the wave functions of the interactions between electrons in the air and the light photons/wave functions. I'm guessing that this text highly compressed explanation might be too garbled to be useful. Bottom line - there is an underlying wave-like function that determines where photons end up and it gets bent in a similar way light waves do. I'll have to think of how to do a video thats a bit better a description!
There's a lot of miraging on highways inland from me in central Queensland, Australia. Unfortunately it doesn't stop people overtaking when they clearly don't have good vision of the road ahead.
The photo of the road in Australia I showed in the video is about the area you seem tio be describing. If you look at the most distant part of the road, its filled in by a refection of the sky. I can see the issues you are talking about - with the extreme heat it could sure obscure vehicles and other things ahead.
Ooooooops, you very nearly disproved the flat Earth theory. Early hours ten nautical miles from Liverpool there are times when the City is noticeable elevated from the horizon just like Superman lifting New York. Abnormal refraction is another term. The crew were not amused by me wakening them at 05:00.
Sorry to all the flat Earthers :) Just looked on google maps - looks like the areas around Liverpool is flat so no mountains to help confine a region of cooler air as in the case of the Fraser River valley. I wonder if the water is cold at times and creates a nice cool layer of air over its surface. Is the shoreline stretched when that happens? That could be a Fata Morgana rather than the simpler superior mirage. Situation probably similar to Lake Ontario which is known for views like you describe.
@@ElectromagneticVideos Liverpool coast line does not have much elevation the City itself is partly on a hill. The river Mersey narrows and is very fast flowing so I would expect a delta T of 2 -4 deg C with respect to the Irish sea temperature. Looking from Birkenhead on the Wirral (the peninsular opposite Liverpool) you sometimes see a temperature inversion and a mist about 15 meter above the river ceiling at 50 meters, Liverpool's Cathedrals (yes two) just visible above. When looking north on a hot afternoon you can sometimes make out Blackpool tower 54 miles away, the tower is 158 meters (518 feet). The coast also has a shimmering reflection. The climate in the Wirral is unpredictable by the national weather service as the prevailing winds are lifted over the Welsh mountains dumping the rain on Manchester, the Dee estuary is generally warmer than The Mersey so we have a microclimate 2 _ degrees above predicted. Very interesting explanation of optical anomalies, I hope the Flearthers take heed and before they jump to conclusions remember that light can be distorted as can their thinking. Best.
@@ElectromagneticVideos Fata Morgana seems to fit some observations although I think we have several different optical events depending on conditions. The river Mersey separates the Wirral Peninsular and Liverpool, it is a fast flowing tidal river which in the early morning will have a level of mist 20 meters ceiling at 100 meters the two Cathedrals visible above. When approaching Liverpool the coastline is low and on a hot day the City of Liverpool appears to levitate just like when Superman lifted New York. Blackpool Tower about 54 miles north is 158 meters tall and is sometimes seen from the Wirral thus is proving without any doubt that the Oblate Spheroid is in fact flat ? or it could be abnormal refraction and other optical phenomena . The Wirral peninsular has a micro climate due to the prevailing westerly winds lifting clouds over the Welsh mountains and over the warmer water of the River Dee thus increasing the cloud density which then proceed east to deliver rain on Manchester much to the delight of Liverpudlians, the Met office frequently incorrectly forecast Wirral weather. Very interesting subject which my Dad would have been more qualified to discuss...... Subject suggestion: Halos and tropospheric refraction from particulates and ice crystals, (or weather modification 'chem' trails if thats your bag.) Very interesting thank you and my best wishes to Canada from Wirral UK
Nice explanation, examples and diagrams. Through me off a little, as I had never heard mirage pronounced with a hard g before, always with a soft g (more like a zh sound) as in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7Lh_hFJsvrQ.html .
If you average the deflection of the laser in the toaster experiment, could you use the average deflection and take a series of measurements of actual air temperature vs deflection and get an estimate of the temperature of the air through which the laser light passed ?
Could write some software to step though each frame of the laser dot video to determine the center of the dot and do the averaging. Problem is though the deflection actually depends on the rate of change in index of as one goes from hot to cold so for a toaster situation the rate of change is not uniform and can depend where the light passes though the hot-could boundary. I had to do some adjustment of toaster position to maximize the deflection.
Amazing. I was convinced the road reflections was due solely to Fresnel's law and not related to thermal conditions. If Fresnel's law is in effect, I'm not sure how you would ever distinguish it from a normal temp gradient mirage. Even headlamps reflecting from the road at night could be attributed to the air temperature. Looks like the phenomena is more complex than I assumed. Thanks!
Funny - I did a fair bit of thinking about how how it compares to a regular Fresnel type refection. I think in this situation the angle between the incident and reflected rays is pretty much determined (and constant) based on the temperature (density) gradient, as opposed to being determined by the angle of incidence. However, presumably as the incident angle changes, that also changes how much of a heat gradient it sees and for how long (before it may hit the road surface), so I'm not sure if that may somewhat mimic Fennel behaviour of incident = reflected angle. The other difference is probably lack of polarization since we are bending the light rather than reflecting on a surface like water. A neat experiment would be to see if polarized sunglasses can confirm this.
But what if I want to demagnetize an entire door?? I have one of those magnet closing screen doors on one side of my French doors and any time the animals fly through there with any force, the closure magnet will fling back and stick to the metal/magnetic door and then bugs get in the house! I’m trying to figure out anyyy solution that’s inexpensive like this! Thx 😊
When we pulled the knob and tube out of our 1930’s house, we found scar marks on the the walls where there were burn marks and bare wire was running between the knobs 😬 must’ve been a space heater or something plugged into that circuit.
Yikes! Its scary how close some places may have come to burning down. So was the wire touching the walls where it left burn marks? If it was just the radiant heat from wire glowing red hot, thats even more amazing.
@@ElectromagneticVideos The house had settled a bit, so one of the nobs had gotten pretty close to the wall but not close enough to where it was touching, that’s what I was thinking. It must’ve got glowing red! And GET THIS! There was another wall where someone had blown in newspaper, shredded insulation that had incinerated inside the wall on the same circuit. It is amazing this place hadn’t burned down. I should’ve took pictures, it was back in 2006. We did a remodel and the contractor was going to take it down to studs but he called me one day and said “you got to come see this” over the studs was lap and grooved hardwood paneling. This is an Everett Washington where there was a bunch of lumber and wood mills like 100 years ago. Found lots of burnt newspaper in the walls, but it looks like it didn’t get enough oxygen to light up tho. 🔥
@@RussShawTV Wow! "newspaper, shredded insulation that had incinerated inside the wall" When researching this video I had come across the issues of insulation being blown in and on top of knob and tube. Interesting to hear a first hand account - and agree - amazing it didnt burn down. Never thought about a house settling and shifting to have that effect but makes sense - particularly a wooden house that has aged over a hundred years. Everett - have visited there (Boeing plant!) - my brother is in the Vancouver area so I know your area - wonderful part of the world!
I didn't know wiring issues were actually a common for them. Strange and unfortunate given that it would only be a small part of the manufacturing process, and getting it right would hardly cost more when they were building them.
In a residential home, EVERYONE should ALWAYS use commercial grade outlets in their house. The $1.29 outlets is too cheap and substandard. Spend the $4.00 for a commercial outlet.
To add to that - with the cost of installation labour these days being so much more than the cost of the outlet(s), it really doesn't make sense to skimp and save a few $ per outlet.
Just wanted to say thanks for this vid. I make jewellery and constantly battle magnetized pliers grabbing onto random bits i didn't actually want picked up lol. Now i have a solution and it's surprisingly cheap too! thanks for saving what remains of my sanity
Glad I was able to help! Just so you are aware, some of these gizmos are better made than others, inducing some which were apparently sold without the magnets inside. So if the first one you get doesn't work well. try another from a different brand or source.
@@bevakathedementedraccoon Actually price doesn't seem to be a good indicator of which are good and which dont work well. So maybe try a cheap one and if that doesn't work, try one that looks a bit different (same genera shape, but clearing from a different manufacturer such as sharper/rounder corners, lettering on the plastic or not etc). Or, get one from a local hardware store, which supports the local community, and if it doesn't work, you can easily return it.
@@ElectromagneticVideos sadly my local guy shut up shop during covid. So i'll go amazon cheap first, n know what to look for if i need a better one later. Thanks again
I could be wrong about this, but i think those "hairs" you were starting to see on the wire might have been the rubber insulation being extruded through the cotton/fabric insulation.
I think your 100% right. I was narrating the video as I did it. Looking at it afterwards with the better view on the video screen than from eyes at a distance, it does look like that which makes a lot of sense with the rubber melting and probably expanding a bit, and maybe even boiling/offgassing inside a bit to add a bit of pressure.
Hello, I placed a Bluetooth speaker next to a Loewe CRT TV (Phillips tube) and after 10 minutes I noticed a rainbow spot in the lower corner..) I removed the speaker and the spot disappeared, the TV also rebooted, but a small gray spot (or light spot) remained in the corner. The transistor works, a characteristic click when turned on... but the spot in the corner still remained..) Please tell me, will this go away on its own?
If you let the TV really cool down without running it (ie overnight) and then turn it on, the internal degausser should activate a max strength and with some luck after a few days fix everything. But if it doesn't go away, you need something that will generate a localized AC field. These days the most easily available device is a soldering gun as shown here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mGK8oYdEqyE.htmlsi=wYM5L-MO9wzePwc9&t=533 . Note that its a solder gun. not a soldering iron (which hardly generates any field at all). With the gun on, move it slowly towards the spot and when the wavy rainbows seem to cover the spot, move it SLOWLY away till the wavy rainbows are NO LONGER VISIBLE BEFORE turning the soldering gun off. If the sport remains after turning the gun off, repeat bring the gun a bit closer to the spot, and again a bit closer until the spot is no longer visible when the gun is off. Be careful - the soldering gun tip gets hot which can burn/melt plastic on the TV if touched (or fingers!). Good luck!
@@ElectromagneticVideos yes, but there is no rainbow, there is only a small gray spot (brightness), especially when you turn on the white background, it is visible. Is this the cause of demagnetization or another reason?
@@tdmax2288 Very likely magnetization. A spot like that is typical of a small amount of magnetization shifting the electron beams just a bit so after passing though the shadow mask they don't line up well with the phosphor dots/stripes. If all three color beams are shifted just a bit and by a similar amount you can see a darkening. I have usually seen colored spots on dot pattern tubes because the shift often favors one or more of the primary colors. A stripe tube (which yours probably is ) could more easily get a darkened spot.
@@tdmax2288 Thats sounds lot like localized magnetization shifting things. Having said that, it all could have been there before you brought the magnet near it. We all tend to not notice stuff like that unless looking for it. Its actually amazing how poorly color CRTs can converged and not have viewers notice.
I haven't had to deal with such weak ferrites, but AlNiCo compositions a low enough coercivity that they're easily demagnetized. Always have to keep them shunted and away from NdFeB magnets. I once had to do a bunch of testing with mortar fuze components that used AlNiCo cores, and I had to make a jig to remagnetize them. I guess that's the sort of inconvenience that happens when you try to reuse something that was meant to be used once before exploding.
So I'm really curious having never had anything to do with explosives. What do you use the magnets for - some sort of fuse or trigger? I would guess the shock of an explosion would also tend to demagnetize them ...
@@ElectromagneticVideos A lot of munitions fuzes have to do elaborate things where timing and sensing is required. Where some of those things used to be implemented mechanically with clockwork, it's all done electronically now. The problem then is getting electrical energy to power the microcontroller(s) in a way that can have a long shelf life (i.e. no active electrochemical cells). There are setback and spin-activated dry-charged cells, pyrotechnic generators, and other stuff, but a lot just use a once-through linear electric generator activated by setback. A tiny magnet gets snapped through a coil by its own inertia, which generates a single pulse which can be stored and used to power everything during flight. That poor generator only does its thing once before it (and the rest of the circuitry) gets destroyed by the main charge.
@@PSUQDPICHQIEIWC Thats amazing. - and clever! Almost infinite shelf life and probably just e enough power to get things done. "That poor generator only does its thing once before it ... gets destroyed" I guess that so true for so many of our sophisticated weapons these days. And for many other things, microelectronics has become so cheap they are essentially expendable - RFID tags immediately come to mind.
Did it a few years ago! Here it is : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lFdSXTKsKwA.html Also did it in various other typical situations. Here is playllist with those videos. ru-vid.com/group/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY
This is not a real world test. If you have a bundle in a house not all cables would be carrying the max current (or 50% over) at any one time. If you have a concern use a thermal gun to check the temp.rise. Or use your hand to check for heat. Warm is normal, hot is not. .
I had no idea they get tripped by RF! I'm a bit surprised that GFCI's have the HF response to even register HF. I can see AFCIs mistaking HF for the noise and harmonics from an arc.
@@ElectromagneticVideos I have had both HF and VHF trip them. For HF it is more likely to happen if the circuit is long, or has a long extension cord plugged into it. (Go figure; everything is an antenna!)
@@PelDaddy Interesting! I actually have a number of HF transceivers from a previous company was a pioneer in high speed modems and networking for military and commercial applications. I probably wont get to experimenting with any of that soon but it would make an interesting video.
The guy coughed during the voice over of him being close to the smoke in the video.. thats pretty weird.. he kinda reminds me of methias wendell the wood gear dude on youtube for some reason..
I had never heard of methias wendell - looked up his channel funny I do see a similarly in how he presents his videos. Cough - there were a few more coughs which were ll edited out - but that one came at the perfect time to mention how bad the burning plastic smoke is.
Man, even for something so simple (the concept I mean, compared to deeper fields of knowledge) the setup and work to make your video is through the roof. Basically, I am just letting you know that I know. Awesome video. You have a nice aura for a video - regular people talk. Rock on.
Thanks! I really appreciate that! You know, you probably one of the few who understood how much time and setup it takes to do something like this. My setup for this type of test has also improved over time - bigger variac, more instrumentation, and most notably a really good thermal camera kindly provided by a manufacturer (Kaiweets) who saw some of the previous videos. "You have a nice aura for a video - regular people talk" - wonderful to hear - thats exactly what I am going for. In particular, trying to trying to demo science, engineering, or technology in a way that is understandable to everyone without the need of years of in-depth science and math background. Its taking a while but I'm gradually learning what works best for RU-vid viewers.
A typical extension cable - thinner wire and often in a tighter bundle is certainly more vulnerable to this. Bottom line - the implications of any bundle of cables carrying significant current should be considered carefully.
Thanks! Whats even more amazing is how hot cables get when surrounded by modern insulation in a typical (Canadian/US) 2x4 stud wall. I did a bunch of videos with fibreglass, rigid foam, and spray foam a few years ago - a bit of an eye opener!
