Lines of Light: How Analog Television Works

Very nice work.

The clearest and simplest explanation of a CRT I've seen on the net. Thank you

I remember back in the 1970s there was an over the air subscription tv channel that would broadcast a scrambled signal. The video signal was scrambled by messing up the horizontal sync pulses with a sine wave. The audio was heterodyned out of hearing range. The idea was you rented a decoder box and subscribed to their service. Someone came up with a "kit" to build your own decoder and that was kind of the beginning of the end.

Electronics, even the kind that we've "outgrown", never stops being magical to me

The high pitch whenever the TV was on screen was mind-numbing...thanks for calling this 31-year-old "young"

The amount of thought you've put into this video is directly reflected into its quality. Thank you for this video.

In my opinion, the three best technology channels are 8-Bit Guy, Techmoan, and Technology Connections. It's amazing that a channel with only 18k subs is producing such high quality content. Please keep up the good work.

I was a TV & appliance salesman in the early 2000s. We sold CRT, Rear projection, DLP, LCD projection, LCD, and plasma TVs. I look forward to seeing more explanations of how the technology works, since at the time all we had was manufacturer info and limited info available at libraries and almost nothing online.

I'm working my way from your newest to older videos for weeks now and this is one of the best with all your humor and voice acting in the narration aswell as the outstanding visualisation. also it's the most comprehensive and accessible explanation of a CRT i have ever seen.

I'm an electronics technician and I've worked for a TV station, so the whole operation of a TV is familiar to me. I want to congratulate you for the video that you were able to explain in a language understandable to most. 👏🏻👏🏻👏🏻👏🏻👏🏻

Very good description of the basics. 'm an old guy and made my living in the 60's and 70's servicing these sets. I worked for a dealer that sold Zenith, Magnavox, and Motorola/Quasar. We made service calls to people's homes and carried two big caddies full of tubes. It was an art to set up convergence on a 3 gun delta configured CRT/picture tube. It was said the mark of a good technician was knowing when to quit...

It's crazy to think about how advanced all of this sounds. Kind of a marvel, even compared to technology today. Awesome video, thanks!

I am an university professor and the one thing I can say is: even though their might be errors (we are all human)you are an amazing educator which is not easy to achieve, many people might have the knowledge but explaining things is a very different sort of act, plus making it enjoyable and straightforward is a pretty difficult task. You don't have to be a wizard to appreciate you are doing a lot of research and preparation to create your videos. My congratulations!!! And please keep the great work coming.

I really admire the amount of effort you put into the production of your videos, you even go as far to make subtitles and as someone who watches everything with subs if it's available i appreciate that alot, thanks for making such interesting content man.

I've watched a lot of videos on how CRTs work but I never really understood it until now. Thank you so much for breaking things down to the individual components and then showing what the each do to build the image. I've never seen anyone do that before.

I'm an old dude (67 years old) and you have explained how CRT's work in a way that even I can understand. This is an excellent video. Very well produced, and I appreciate it. I've seen a few other videos done by Technology Connections and now I'm gonna subscribe and support. By the way, I lost my ability to hear the waves described at 5:40 long ago (30-40 years ago).

Your videos have given me a much greater appreciation of the use of analog television/VCRs as a modern motif. I really like ContraPoints a lot more now. I'd love to see you discuss the motif of using obsolete devices in both nonfiction and fiction set in the current day.

This was awesome and interesting. You stay on point and give very CLEAR analogies, examples and show
interesting components (the small CRT without the YOKE attached, and then attached the yoke so people
now know why it looked that way) all this while straying strictly on point! Most professionals can't do that!

Just because it is considered outdated technology does not mean that it was simple technology. Thank you for the breakdown.

Impressive work done here. There should be an Award for such accomplishments.

It's really cool watching this video on a CRT television. I just kept the old family TV when we upgraded to a flat screen in 2011, and it still works as it used to. Now I can watch the mechanics of analog television play out as it's being explained to me, and that's just so damn cool. I will admit though, having the artificial screech of the video on top of the one that I can pretty easily tune out on my own in your demonstration was absolute murder to my ears.

I have to thank you, SO MUCH. When I find a channel I like...I watch them constantly. Like, ALL the time. You have taken over my number one spot, and I'm learning SO MUCH thanks to you, and you alone! Such a great channel, can't thank you enough ❤️

Good job! I found this on the Internet: The CRT TVs average (and median) lifespan is recorded as 15 years, compared to 6 years for the LCD and LED TVs (Fig. 2). I still have a Sony Trinitron from the nineties and it works pretty well

me: ha, I can totally hear the sound and I'm over 25.
*pauses the video* oh wait i can still hear it. uh oh.

This was clearly, extremely difficult to make. I commend you for the energy and time you put into something you obviously care about. This was amazing... not sure if it matters but this is honestly on par with The Secret Life of Machines, just a little more serious.

I knew all this stuff. I didn't learn anything new. But the graphical explanation was so lucid and compelling I applaud anyone who can explain this tricky concept in such a clear, visual way! You got me! I've subscribed!

Ive been an audiophile for a while but only recently have I gotten into the video side of media with the CRT becoming the focal point of a better vintage video game experience. I love analog technology and how elegant it is, you have a way to bring it to life. Thanks fir the tv data download and futiure ones too.
liked and subscribed

Awesome video! Im always amazed at how complicated simple things are when you really start asking questions.

Even when you're explaining something I already understand well, you do it in such a clear and entertaining way (including a judicious use of humor), that I'm happy to watch it. Your presentations are always excellent, and your explanations are always clear and concise. Keep up the great work!

I have recently acquired a 14" Philips CRT TV from my aunt who didn't use it anymore, to play my Xbox 360. I was fascinated by how the image looked, I knew how it worked sorta, from when I was very young at around the time of this technology's demise, my dad explained it to me with terms that were understandable to my 5-7 year old self at the time..
So I simply looked up "How CRT TVs work" and this was the first result. Incredible work, I knew about scanlines and interlacing, but I had no idea my beloved TV was nothing but a single dot of light moving insanely fast! Truly fascinating how it can build the images of my games. I also didn't know about the high-pitched noise, thought the TV was defective.
Again, very nice work! Will look for the color episode if it exists (even though I have an idea of how it works).

Jeez dude, I think I'd be hard-pressed to find a bettery explanation of how CRT TV's worked anywhere else. Such an amazingly well done video. Thanks for the wonderful content, you're one of my absolute favorite channels!

As usual, amazing work. I don't think we can thank you enough for making these videos.

You know, I grew up with TV's like this and I never gave a thought to how they worked. In fact watching your video you can actually see what would become a transition from the old oscilloscopes to the TV signals we all watched. I for one remember playing with the horizontal and vertical holds as a child and watching what they did to the picture :). Kudos to you sir.

I love your channel, been on a binge. You explain things so well and keep it interesting. I actually understand a lot more about tech I never could grasp before. Also, I'm 30, but that high pitched noise broke my brain and freaked my cat out

I actually had a black and white tv with the hold adjustments and such as a child. I functionally figured out how to use them. But, it's really cool to see the coding, and science that made those controls necessary, and just how cool, and nerdy they really were. Thanks man. I also really enjoyed your video on line 21. Mind blowing.

This has to be one of the top videos explaining something like analog TV. I also love the ending shot of the LED flying off the fan. It shows that we’re all human and subject to Murphy’s Law.

I hope this channel gets many many subscribers, the content is just too good to let it pass, keep this videos coming man, great job!

This was the most easy to follow and insightful introduction to television I've ever seen.... or even conceived of. Thanks!

Brings back a lot of memories...I had not thought about "horizontal hold" and "vertical hold" in years and years and years.
I'm only on my third video watching this channel, and I am LOVING this. Thanks so much!

Wow, that's amazing, a lot to wrap my head around, I may need to watch this twice but holy cow that was really good thank you!
p. s. nearly 40 and can still hear the sound 😅 in fact I can still here much higher frequencies.

This video was so beautifully detailed and well explained with example shots on the actual TV

I'd love a follow-up on how color analog tv's work. This was extremely insightful and easy to understand. Amazing how people who didn't fully understand the working behind something were able to harness it to create television. That has to be a near-miracle.

You have a fantastic talent for explaining difficult concepts in easy to grasp steps. Keep up the great work!

Fantastic information ! There are 4 coils on the Crookes Tube Yoke, 2 coils for vertical and 2 coils for Horizontal deflection. Two circuits, for the coils . The third circuit, lamp-tracer brightness is controlled by the Amplitude, into the Crookes tube electron gun, provided high-voltage from the flyback transformer. What a machine !

This guy is really good. He's very knowledgeable and the best I've seen at explaining these things.

I am a retired video surveillance field engineer, and this was one of the best explanations of this tech I have ever seen.. well done!

Having worked in the electronics industry for RCA & GE Electronics this is actually pretty on point. I was REALLY questioning how accurate this video was going to be.

Hey, my teacher in my electricity and magnetism class briefly discussed the physics behind a cathode-ray tube works, but left out the rest of how the TV works. I know this is an older video, but perfect timing for my recommendation!

This was so well put together! You've got some great design and editing skills to go with your ability to explain in layman's terms!

I am most certainly not one but after binge watching your videos the last few days I feel like an electro mechanical engineer haha but seriously, you make learning about complicated apparatuses and processes easy and accessible

The best part of this video was how they aired closed captioning on an anolog tv by using a scan line below the screens display area. This has to be one od the best explanations of a crt tv. Great video!

I was a TV repairmen for over 30 years. This video shows a very good explanation of how a TV works. I have to praise the content producer for many a very accurate explanation of how a TV and explain it where it can be understood to people with no technical training.

I collect and restore classic arcade games, so I know a fair amount about CRTs. I repair them regularly to keep games alive. Your informative, clear explanation of this complex technology still kept my interest.

I spent my first working years in the 80's repairing consumer electronics, mostly televisions. Excellent job on the video. Very well done.

The "black level" in an analog signal is actually 7.5 on a scale from 0 to 100. The blanking level is at 0 and the lowest part of the signal, known as a "sync pulse" is well below the blanking level, at -40.

Awesome, you are a highly clued up young man. Your easy to follow descriptions are wonderful. I wish you good luck with your channel.
Back in the 70s, my uncle, had a radio and tv business, at the tender age of 16 , I worked for him at weekends. Most TVs were valve (tube) sets, the new colour sets were hybrid, with valves and the new transistors in them. With the old valve set you had about 15000 to 2000 volt HT on the final anode to the tube, to test this you held an uninsulated screwdriver about 1/4 inch away from the high voltage anode to see how big an arc you could draw from the valve, if you got to 3/8 of an inch, all was good. Most faults were from burnt out line output valves, easy fix back then, unplug set, take off back cover, pull out old valve and replace with new one.
We had 405 lines at 50 cycles in the UK then, in 1968 625 lines in colour were introduced, that made a big difference to picture quality, the system we had was PAL.
As for NTSC, we jokingly called it Never the same color twice. Whatever, it was fun back then, I really don't why im still alive after what we used to do with electricity.
Im an electrical refrigeration engineer now, still alive at 64.
Bugger.

It is kind of delightful that we can now see the most-replayed part of the video, and it's a rather interactive one - the part where we hear the CRT noise sample. It seems a lot of us are testing our hearing!
At the gray old age of 35 I'm starting to lose that range of hearing, and I have to mash my ear against my laptop's speaker to hear it... but I can still hear my new LED bulbs across the room lmao. Out with one high-pitched hum, and in with another, I guess.

I enjoy building tube circuits. Magic eye eq setup is very cool to watch. And I like using my analog crt oscilloscope over the modern digital. I learned more from using it that I wouldn’t have if I started with a digital. No auto math functions on the analog. Exercise your brain instead of using the digital. But I use the digital also. They are both great.

I not only heard the intentional example of the "TV noise" but heard something like it while you were demonstrating with the case off. I have a lot of trouble with electronics around my home because I can still hear those ranges (I'm 30). I recently found out that my wireless phone base makes a high electrical tone when the answering machine number indicator is blinking. Took me ages to figure out what was making it. Only upside is that I can usually hear an electrical problem before other symptoms like charring or melting start to appear.

It's astounding how difficult it was to decode or manipulate signals before the digital age. You really had to be ingenious to get around the limitations.

man, as a kid that noise from a crt would drive me crazy! I could always hear when the TV had been left on. now that I'm older I'm a little sad that I couldn't hear it anymore. stupid hearing loss. stupid aging process.
love the content! keep it up!

I love how you constantly change the video to be authentic to what you're talking about. Super cool.

Wow extremely excellent videos and you show the internal working as well! Ive worked with electronics for about 17 years and your videos are spot on!

Im a bit behind but just wanna say you are increasingly becoming one of my favroite channels to watch, cause i love learning about tech, especially older tech. If you do not mind, could i suggest a topic? Since this video mentions raster displays, which is what tvs of the day used, could you do a video on vector displays, like what the vectrex used? Ive always been facinated in crts and recently learned about the two types of crt displays, raster and vector, and would love to see someone like you explain them. Thankyou for you videos, keep up the spread of knowledge, i look forward to your videos :)

This tutorial on the technologies of television is one of the best I've experienced ever. The presenter is articulate and explains the subject matter in the most unambiguous manner. Thank you.

This was a very clear, and visual explanation, thank you! I think I'll use part of it in an offline presentation about old CRT-s, giving you full credit, of course!

Good job explaining and nice video. My high school electronics class was the last class to build a TV from parts as our final project. That number 15,750 was drilled into my head so hard that I remember it today. Our school bordered Radio Valve Road which was the home of a RCA tube plant that supplied our class with all RCA parts. It was a fantastic experience to actually build something fairly complex and get it working and encouraged me toward electronics as a career.

You should do a video on how a Capacitance Electronic Discs works. It was a rare format made by RCA in the 70's that was a vinyl record with extremely small grooves to display video and audio. Instead of a needle going up and down to create sound, the needle would have different levels of electrical resistance based on the groove and then transfer that information to produce audio and video. It came out when VHS and Beta was hitting the market so it flopped. It's incredibly rare.

Dude, this is incredibly well done. I was looking for some in depth explanations of CRT TVs as the ones I keep finding are too high level and I wanted more electronics details. This was well made, well edited, technically above and beyond (really impressed me with the deconstructed TV with the power supply and adjusting the deflection of the electron gun), and just what I was looking for. I guess I'm still curious how an analog signal from the air was turned into deflection and intensity information at 15khz without digital circuits, seems wild to me still.

Fun fact, you can remove the flyback transformer from old tvs and make a high frequency power supply, for some really cool electrical effects, including large sparking arc gaps, and ozone generators.

Thanks for this video now I know how that box we have in the living room works. As a kid I was fascinated with the black & white TV. Now I’m 50 and am really amazed how humans create things. Keep it coming and really love how you explain things. Much support from the Philippines.

My used to have his workshop where he was fixing TV sets radios and vcrs. I was around age of 10 and was bit curious how those things worked. Nicely explained. Many times on tvs he had to replace the deflection yoke as people would be able to see horizontal line. Or the HV transformer had to be replaced

Absolutely amazing description of CRT operation!
Incredible what could be done long before computers existed. The complexity involved with CRT analog TV compared with pixel-mapping an LCD is phenomenal. But it worked to provide information and entertainment for millions of people for decades!
Funny you should mention the high frequency noise of the horizontal oscillator. I remember as a kid complaining to my parents about the high-pitched noise the TV would make, and they were like: "What noise?"
Look forward to your description of color CRT analog TV operation.

CRT needs 12k to 25K volts depending upon size and if black and white or color. I had special tools to discharge the stored energy in the CRT and another to measure the high voltage. Replacing a big color CRT was allways a little scarry. Great description of early television.

I enjoyed this very much 😁
Great job with all the details
Thank you for explaining it in a way that makes sense 👍

Absolutely fantastic explanation, an inspired video very well explained. Top marks and thanks for presenting this in a way that everybody can understand. Now subbed ;)

You correctly stated that the amplitude of the visual carrier of an analog TV signal dictates the brightness of the 'flying spot' that renders the image on the receiver CRT. What is often overlooked is that the relationship between carrier level and image brightness is inverse. In English, that means that as the visual carrier power increases, the image becomes darker. The transmitter actually broadcasts a negative image that is inverted again in the video amplification stages of the TV receiver before it is passed on to the picture tube.
This might sound a bit counter intuitive, but there are a couple of very good reasons to do this. First, as analog TV signals degrade, either over long distances or in heavy interference, the picture quality degrades slowly. The image will become snowy and somewhat indistinct, but will remain watchable until the picture signal fades out completely. As you pointed out, the synchronization and framing pulses in the horizontal and vertical blanking intervals are transmitted at 'blacker than black' video levels, which, were the carrier not inverted, would be represented by carrier cutoff, or no carrier at all. In a less than ideal reception scenario, these sync pulses would be attenuated before the rest of the active video and lost. Without these synchronization pulses, all the rest of the video would become an unwatchable mess. By inverting the video, blacker than black sync pulses are represented by the maximum carrier level that the transmitter can produce. This means that these signals are the most powerful and therefore the last to fade, so the receiver will continue to produce a watchable picture, even if the picture quality is severely attenuated.
Another reason for inverting the video at the transmitter has to do with operating costs (naturally). In order to maintain good picture quality, the high power amplifier stages of an analog TV transmitter must exhibit exceptional linearity. This requirement dictates that these amplifiers be biased for minimal distortion in either class A or class AB mode. Without going into a lot of amplifier theory, linear amplifiers trade off high picture quality for low energy efficiency. A high powered analog TV transmitter literally sucks in electricity during operation. Were the video not inverted, the transmitter would have to work a lot harder since most of the active video, on average, depicts high average picture levels (APL). By inverting the video signal, the transmitter only has to run full blast during the sync pulses, which account for less than 2% of the transmitted video signal. Since full power TV transmitters can consume $8,000-$10,000 in power monthly, anything that seriously improves power efficiency is going to be implemented.

This is around the 6th video I've watched to try and learn the basics about video transmitting and how it works. It's like watching all the previous 5 combined and improved lol. Very easy to comprehend the explanations and descriptions.

To my knowledge, you're honestly the first person to ACTUALLY explain in detail how analog TV works, before you, I had to look at old PDFs and stuff.
Keep it up and I'm SURE you'll get many thousands of subscribers!

This was fantastic! thanks. perfect example of how a passionate Clip-Share content creator produces better content then the History and TLC combined.
you made mention at the beginning about todays digital imaging and how its kinda "meh" in its operation (Paraphrasing). As a kid CD's where new and I was fascinated by them. We had a huge library of Vinyl records so to see CDs I was in Awe. As I grew up and the world became more digital i look back at a Vinyl record and i'm more in awe of that technology then digital sound. think about it some one came up with this crazy idea to capture sound by scaping it in to plastic.

Wanna say, appreciate the two epilepsy warnings. Was able to scroll down in time. It's a very thoughtful and meaningful thing to do and one I wish more creators did.

Good explanation, but it made me realise that there is now a whole generation that doesn't remember CRT TV's! It's weird that something that was so ubiquitous is now considered obsolete or 'retro' by some people. And yes, in 2019 I still have many CRT TV's and monitors. I even have a few vector monitors.

I watch several old Cathode Ray Dude episodes, and Clip-Share decides I would be interested in your older episodes as well. Thank you Clip-Share! Very good episode, I always learn from and enjoy your channel; then and now.

I worked on old army helicopters and the multifunction display (mfd) was cathode ray tube in the kiowa ,I understood how cathode ray tubes (crt) operated but not how it was controlled, this is super cool!

There is nothing wrong with your television set. Do not attempt to adjust the picture. We are controlling transmission. If we wish to make it louder, we will bring up the volume. If we wish to make it softer, we will tune it to a whisper. We will control the horizontal. We will control the vertical. We can roll the image; make it flutter. We can change the focus to a soft blur or sharpen it to crystal clarity. For the next hour, sit quietly and we will control all that you see and hear. We repeat: there is nothing wrong with your television set. You are about to participate in a great adventure. You are about to experience the awe and mystery which reaches from the inner mind to the outer limits.

good explanation, had a general idea but was always a bit confused as to how a single electron gun did all that work. Basically this video also unintentionally taught me how an oscilloscope works.

The inventor was extremely smart to be able to figure all this stuff out. I know that you do a lot of research to make your content. You have to be really smart as well to understand everything you research. Kudos

Brilliant explanation!. I used a similar black and white TV, "the one you took apart" to build my steampunk Sega master system. These old bw CRTs still have uses.

Bravo! So much work, so nicely put together and presented

I loved the sound the tv made when turned on, that warm sound of just kicking back nostalgia of a show coming on or a movie! Something modern tv's just don't give.

Got to be one of the best explanations of analogue TV I've seen. The physical demonstrations on an actual CRT worked so much better than a dry text book description.

There is another part that extended lower known as the sync pedestal which is transmitted by the camera and extends a little below the blanking pedestal. I used to work on industrial monitors and viewed the wave form on an oscilloscope .( b&w )

Amazing video, thanks for all the time and effort you putin to this.

Very well done video. Great editing and to-the-point information. I enjoyed it a lot! Subbed

Slow Mo Guys did a great video on capturing the processes different televisions go through to create a picture. Watching a CRT scan line slowly race across a screen is still one of the most satisfying things I’ve ever seen. Here’s the video: clip-share.net/video/3BJU2drrtCM/video.html

Over the years I heard and remembered all the key terms. You are filling all the gaps. Thank you.

This was a phenomenal video! I’ve been interested in old technology for awhile, and you explained this perfectly!

I have a thought experiment I would like to check on.
The current analog TV signal is mostly amplitude modulated to convey its intelligence (with a frequency modulated audio carrier, though that too is carried in an amplitude modulated signal). One problem I keep running into is that amplitude modulation is very easy to interfere with. However, frequency modulation seems to reject just about all interference, though its primary use has traditionally been for audio. What would be the effects as far as both the signal and the performance of TV's using a resemblance to the NTSC and PAL standards that were used, had the entire TV signal been frequency modulated?

I knew all this stuff! (I'm an old timer from the olden days) But I love to hear you explain it! You make it so clear! Thanks!

Oh, I loved messing with CRT's. I used to love taking them apart when I was a kid. (13yrs old).
My uncle is a electronic engineer, and also has a doctorate in computer science. That's why I really got into electronics. Watching him work on various things on the side. Used to fix radios, computers etc.
Anyway, awesome video dude, I love this channel!