Astable 555 timer - 8-bit computer clock - part 1

[@AlanCanon2222]

I just made my 6502 Ben Eater computer say "Hello World." Now coming back here all the way to the beginning to give my now-battered and war torn Ben Eater clock module a check up, and revisit this great old video.

[@cobra646]

By far the best explanation on the 555 that I have seen. As a total beginner this was great.

[@Decco6306]

that's because he doesn't have a thick middle Eastern accent you can't understand

[@ritvikvaishnav3472]

totally agree.

[@Bu7MaiD075]

Kipper Klank as a middle eastern, I agree. damn indians ruined engineering videos.

[@MrPnew1]

@@Bu7MaiD075 yeah stick to the Poppadoms :)

[@ianphil397]

It's also the best visual explanation I've seen of how a decoupling capacitor works. Excellent stuff.

[@Mirandorl]

Forget netflix, I just found my latest binge watching source

[@bobdagamer640]

TheDroidBay yep

[@syrus3k]

Totally. I just realised I have the components to make this too... It's gonna be a long night

[@merofuruya_]

I feel you

[@mdasikkhan1610]

@TheDroidBay I like how the comment has 555 likes hahaha Ah man its not 555 anymore

[@johnjordan3552]

This is better than anime, and possibly at least 1.667 something times more entertaining than watching hentai

[@amyhicox2578]

As a kid who grew up in the early 80s playing with those radio shack “100 in one” breadboard kits, got to my teenage years and said “well that’s cool, but writing code is where it’s at” ... then dove head first into programming and nearly forgot about hardware hacking beyond plugging things into motherboards ... THANK YOU. My 43 year old self still loves to code, but hardware is so unbelievably complicated and impenetrable now. You have rekindled the spirit of playfulness that I first experienced reading those old Forest M Mimms books. I just found your channel, can’t wait to watch the rest. Seriously, thank you.

[@d0nnyr0n]

@The Creeper King lol

[@traeldor]

@ Andrew Hicox I'm with you. Built my first AM radio in the late-middle 70's, and since the middle 80's have been learning multiple coding languages. These videos have rekindled a hunger for the breadboards. Now to get my wife to understand. LOL

[@amorag59]

​@@BillAnt We need less incels in the world, not more!

[@djcsdy2]

Looking back at them, the Forrest M. Mims books are terrible, or at least “Getting Started in Electronics” is. That’s probably why you gave up on hardware. It’s certainly what happened to me. It goes straight from explaining what an electron is to giving example circuits with totally inadequate explanations of how they work. Digital signalling circuits are covered but it doesn’t even explain what a pull-up or pull-down resistor is for, or even tell you what they’re called. There are just these mystery resistors in the example circuits that aren’t even mentioned in the text. I read it cover to cover and had no idea what was going on. I don’t know why people like them so much but I’m pretty sure it’s just the cute illustrations and the novelty of a published book being written on graph paper. As an instructive text, for me it was worse than useless, and set my interest in electronics back ten years.

[@laurencevanhelsuwe3052]

Have a look at the Tinkerforge components.. as a coder you will *love* them. I've created amazing projects with them.. the end results make you look like you're an electronics pro.

[@acf2802]

You got to watch out for those ±100% tolerance Chinese capacitors.

[@markusepple6204]

This is bought cheap not as a timing capatitor, but as a DC-filter it is working fine.

[@lavalamp3773]

If we allow for -100% tolerance, I got some 1 GF capacitors to sell you.

[@Synthetica9]

@@lavalamp3773 ah, yes, I've also seen pieces of wire before

[@tayler6000]

This is the funniest hardware related thing I’ve read in my entire life

[@wreckingangel]

This is why Electrical Engineers always look in the datasheet first, even for a simple capacitor ;) Electrolytic capacitors age, the electrolyte dries out over time, this is why it is overdimensioned. 1uf is the guaranteed capacity at the end of it's rated lifetime. Electrolytic capacitors are usually used to filter DC Voltage for power supplies and stuff like that. They are normally run at around 75% of their rated Voltage and at elevated temperatures which accelerates ageing, if it had only 1uf from the start it would die fast. Electrolytics are a bad (and expensive) choice in this case, for a circuit like this a ceramic capacitor would be better but sometimes you got to work with what you have at hand.

[@aidencoder]

I never "got" electrical engineering, but instead became a software engineer. Ben's explanations bridge the gap somehow for me, and make electronics seem more like programming. I like this.

[@PPSRHD]

Well nearly all computer Innovation is due to electrical and electronics engineering and software just comes later. All initial software was and is made by electrical and electronics engineers as it is extremely low level

[@aidencoder]

@@PPSRHD Yeah and that's all down to mathematicians and physicists. Electronics just comes later. Not sure what your point is. I don't think you have one.

[@Lil_electrician]

@@aidencoder im guessing hes trynna say that electrical is harder than software because it goes more in depth....

[@timecubed]

It really does feel like programming. The reason why is mostly because software engineering is based on electronics and hardware stuff. Similarly, programming feels like electrical engineering (at low levels) since both software and hardware are so closely interlinked at low levels (think of programming in C or C++). Edit: I _might_ not be fully accurate here so excuse me if I got something wrong

[@aidencoder]

@@timecubed you're right, software and hardware are equivalent and the distinction is only where you choose your level of abstraction. All software can be implemented in hardware.

[@geraldbull9272]

Really like this chap, he talks down to earth, explains it well, not hyped and above all no music in the background, sanity at last.

[@horrido666]

IKR? I wish he'd do more like this. Everyone else just puts me to sleep.

[@carlospitcher4335]

I have easily seen 20 555 circuit explanations. And I can assure hands down, yours is the best... Thank you!!!!

[@arvinmistry9744]

Great you are the best teacher with detail explanations

[@ericrandall3539]

The way you drew the diagram is, I believe, the reason so many people are finding this so helpful. Showing the 2 resistors and cap all in series on the left is by far the best way to visualize this. I wish more tutorials would show it this way. 10 people will draw this 10 different ways, but for many beginners it won’t click until they see it drawn like this.

[@starkiller1223]

"Showing the 2 resistors and cap all in series on the left is by far the best way to visualize this" I agree 100%

[@jimknight5675]

I’ve been involved in electronics for 43 years and have never seen such a tutorial so clearly explain the function of a 555 timer, you are an excellent teacher and I wish you had been a lecturer at college when I was there.

[@CharlesPanigeo]

13:55 the 0.693 constant is the first three decimals of ln(2). The logarithm comes from inverting the exponential charge/discharge function to solve for the time.

[@NonEss3ntial]

Can you explain this a little more?

[@NonEss3ntial]

How does t=R*C*LN(1-(Vpresent/Vmax) become t=R*C*LN(2)?

[@g73hc3gsv3i]

​@@NonEss3ntial The output voltage of an RC circuit at time t is 𝑉 = 𝑉max*𝑒^-(t/RC) ∴ t = RC*ln(V/Vmax) For an A-stable multivibrator, charging and discharging happen between 2/3Vcc and 1/3Vcc, respectively. As initially it starts from zero charge, ∴ ON time, 𝑡 = (time taken to reach 2/3Vcc - Time taken to reach 1/3Vcc) t = RC [ln(2/3) − ln( 1/3)] = 0.693RC

[@NonEss3ntial]

Thank you so much! I am an EE student and this is still in my notebook of problems to figure out. Thank you thank you thank you. @@g73hc3gsv3i

[@unchayndspersonalaccount7690]

0:00 Introduction and Base Circuit Overview 1:42 Base Circuit In-Depth Explanation 17:58 Fixing Transition Noise 19:22 Fixing Overshoot 23:32 Attaching the Reset Pin to 5V 24:35 Adding Speed Adjustment

[@ch6339]

Man you're incredibly good, I mean your vids are awesome, you're very clear in your explanations !

[@banderfargoyl]

charles beauville I second this emotion. This is just very well done.

[@fernwood]

Yeah I've been trying to understand analog circuits for 3 decades. This video alone might've gotten me over the learning curve.

[@caiopereira1289]

@@fernwood Hey, there are some excelent tutorials on youtube and on the internet that I can show you if you want. What is your interest in them?

[@billtasker4372]

The 555 is difficult to understand but Ben Eater is a great teacher. Thanks.

[@Fittiboy]

the .693 coefficient is approximately ln(2), as the capacitor only charges and discharges half way.

[@peabnuts123]

Thank you

[@microm2078]

It only charges from 2/3Vin to 1/3Vin. The calculation for that would be: 2/3*Vin*exp[-t/(C*R)]=1/3Vin t=ln(2)*C*R. So you where right about the coefficient, but it doesn't charge or discharges half way. Im sure thats what you meant, but just for clarification.

[@yiliangliang5694]

lol I've seen this constant so many times (in Chemistry; physics; etc.) that when I saw .693 in the video I immediately know it's ln(2) lol

[@ZzSlumberzZ]

I knew it seemed familiar!

[@adityathakur7604]

@@yiliangliang5694 especially in electrochemistry and ionic equilibrium lol and chemical kinetics

[@philpesce]

Years ago a fellow engineering friend of mine and I decided to build a circuit with a 555 timer. He’s a mechanical engineer and I’m an aerospace engineer turned software engineer. We had no idea what we were doing but managed to get the timer working. Fast forward to today and I just sent him this video and we are both watching it simultaneously from across the country. This is awesome and I bought the kit! Thank you, Ben!

[@varshneydevansh]

Just a question why you switched the AE to SE as I also seen a lot of AE doing this. Tho. asking as my little brother is about to enter in STEM college and somewhere AE is we are considering.

[@sjgsteve21]

That’s wild man. I’m a mech eng and work in an R&D lab with hydraulics all the time. When he plugged that capacitor across the power lines a light bulb went off and I realized it’s no different than putting an accumulator on the pump supply line to reduce noise. You are a great teacher! Loving these vids

[@shawnmuench]

Holy shit that's a cool connection. I'm not an engineer of any kind, but that makes definite sense intuitively.

[@eritain]

The analogy between electronics is extremely close. Voltage is pressure. Current is, well, current. For any basic electronic circuit you can literally build a hydraulic simulation of it. I think I've seen a learning kit that actually did that ("for children" ... um, yes, I would buy it for "my child").

[@topilinkala1594]

@@eritain When I try to explain how resistance and capacitance work in AC circuit I always talk about seasons. The light pressure from the sun is highest on the summer solitice (northern hemisphere) but that is not the hotest time of the year. Athmosphere acts both as a resitor and an accumulator for the heat. So the max heat is phase shifted to about August. Same thing happens during winter when lowest light pressure is winter solitice, but the coldest time is in January-February.

[@banban8481]

Hello Ben Eater, I want to thank you for your videos and KZbin channel, I first saw your video when I was in high school and just started to learn electronics, and now almost 7-8 years have passed. I became an electrical engineer and chose electronics as my specialization. One of the many reasons is because of you, thank you very much for your tutorials and please keep making them. Maybe for you, it is just a video but for us, it is changing the world.

[@jegarretson]

Capacitors have a tolerance rating, just like resistors. Electrolytic capacitors typically have a tolerance of -20% to +80%, but it's not unheard of for low quality electrolytic caps to have tolerances of -50% to over +100% which explains your "1µF" cap reading as ~2µF. Also, if you were to connect another 1K resistor from the junction of the two timing resistors directly to pin 7, your duty cycle would remain much closer to 50% and would negate the need for the other resistor you added when using the variable resistor. As to the connection from pin 4 to your positive rail, it's generally safer to use a small (

[@robmckennie4203]

if it's a tolerance thing, why are they all off by the same amount in the same direction?

[@John_2143]

my best guess would be that they're all from the same batch, so they all act similarly

[@michaellee9743]

Also I have seen 555 circuits which don't trigger because the charging current is less than the electrolytic capacitor leakage! Electrolytics vary wildly with temperature too, so best to keep the capacitor

[@telefon72]

Because then they can sell 1uF and 2uF capacitors, but only make one.

[@BrightBlueJim]

The key to this is that electrolytic capacitors are use almost exclusively for filtering and DC blocking. In these applications, designers want at least a certain capacitance value, which explains the -20/+80 tolerance. Also, because electrolytic capacitors tend to drift to smaller values as they age, the manufacturers try to design them to start their lives at the high end of their tolerance range. This makes electrolytics generally unsuitable for timing circuits. The same is true for ceramic capacitors using certain ceramic formulations (sorry, I don't know which ones of the top of my head), but they are generally much closer to their rated values than electrolytics. If you want a precise timing circuit, the best bet is to use either polystyrene or polyester capacitors, but in any case, look at the datasheets. Capacitors really AREN'T purely generic components. Of course, it's much harder to find 1 µF capacitors in polystyrene or polyester, so the resistor values also have to change. Not a big deal unless you want a really low frequency, as in this particular circuit.

[@cheesecake667]

Im blown away by your knowledge and explanation skills. WE students need YOU to be a Professor! Then again, you might as well keep producing your awesome videos and reach an even greater number of listeners. I subscribed. Thank you!

[@jeffmerlin2580]

The best 555 explanation I've seen. Having watched the SR-latch video also helped a lot. Thanks!

[@bertieblob3387]

The best description I have come across of how the astable 555 timer configuration works. An exemplary example of how simple, clear thinking can de-mystify something that, initially, can appear complex and difficult to understand.

[@valuedhumanoid6574]

Your grasp on electronics is off the chart. There's no better feeling than leaving a video understanding a concept you had no clue about. So good. That's worth a like and a sub

[@batchrocketproject4720]

I like returning to this video when I need a reminder that there can be order in a complex world. A few years ago I carried the (huge) 555 data sheet around with me for about a month, studying it in every spare moment. This video does a better job than hours of reading. Thank you Mr Eater.

[@davidhanley6437]

I don't think I have ever heard an explanation of 555 operation and circuit design as clear and understandable! Looking forward to watching your other vids. Thanks!

[@Seltyk]

My 8th grade required electronics class had us use the 555 timers without any explanation of how they work or what they do, and now, however many years later, that hole in my mind has been filled. Excellent explanation!

[@robertharold1190]

I received your clock kit as a birthday gift this year. This is the first time I"ve ever look at an IC and really understood it. The way you drew out the diagram, arranged from left to right, was a great breakthrough for me. Thanks! I'm looking forward to building the kit and learning.

[@notanymore9471]

Bro, I’ve been watching videos and not grasping this completely until I watched your video. Thank you for being a great teacher!

[@splitzerjoke]

Wow. Back when I was a kid, I used to be a drummer. Through practice, I accustomed myself to the duration of a second to keep beats constant. When you computed the period for the first time, I immediately knew it was off; the true period must have been something around 1/4 - 1/5 of a second. Almost got it! :) I knew drumming would come in handy sometime haha

[@BillAnt]

Well at least you're marching to the beat of your own drum and not to a 555. ;)

[@tndigi1233]

As someone wo never received any formal Training in Electronics but wo is driven by natural curiosity and an IT job that often takes me close to Electronics , I tried hundreds of Times to wrap my head around these basic components like the 555 or latches and flip flops... I've never seen any better explanations than the ones from Ben... If i could give a hundred thumbs up for every video, I definitely would... Made bis 6502 series a compulsory item in Junior Training courses so that Everyone will get the concept of how a computer actually works...

[@FranciscoLopez-ym6gd]

Hello from Colombia . I normally don't comment , but this is the best explanation that I have seen , and ...... I dont speak English very well :) .

[@monchosalce]

Eso pacho

[@deltakid0]

Pacho u_u hello from Colombia too, the video has auto generated closed captions so while you are learning about 555 you also learn english :)

[@pumpkin6429]

Hello from America. Fuck yeeahh! Bet you dorks wish you where here. 😂

[@noble6430]

@Pumpkin Idk. There's a reason I decided to stay on Reach you know.

[@heh2393]

@@pumpkin6429 What is wrong with you? American exceptionalism maybe?

[@anotheral]

This is the first time I've actually UNDERSTOOD what electrical components are doing, regarding the "duty cycle" section. That was jaw-dropping/eye-opening stuff! THANK YOU

[@aSeaofTroubles]

In 20 minutes I've learned more about circuits than my entire intro class to circuits!

[@skilz8098]

That's because institutions are profitable business and they want your hard earned money to keep you in debt (poor) while they stay rich. They only teach you enough about the topics but force you to learn on your own. Then again it may also come down to the individual institution and professor. They won't teach you everything you need to know in a concise clear manner in the shortest time possible. The want to stretch it out over as much time as possible and even throw in a few bits of confusion just so that you would have to take another course for another semester so they can make a few more thousands of dollars off of you. Now as for Ben on the other hand; he has the knowledge and capability of building such systems and he actually enjoys sharing what he knows through his public KZbin videos. He understands that your time is worth something, so he designs his videos with accuracy and just enough details and information needed to actually understand what is happening within the circuits where all of the mathematics, the circuit diagram, the logic diagram, the truth tables are all taken into consideration and to top it off, he uses breadboards to demonstrate the theory by putting it to practical tests while explaining where all the connections are going to and from for the direction and amount of current from one part to the next. His videos are by far the best illustrations for generally anyone to understand the internal workings of computer hardware, either it be the CPU, RAM or some other device that uses circuitry and memory. This is far more profitable than spending 20 - 80k for a 4 year degree at a University where you still walk away 1/2 confused...

[@crateer]

@@skilz8098 totally depends on the country though, and totally not in europe lol

[@azakusilov]

Dude, your videos are treasure. We need to preserve them, and everyone interested in electronics should see them. There are lots of people who have this knowledge, lots of books and stuff. But many are written in a way that it's very hard to understand for someone new, who just started learning. Your videos are done in a manner in which it's very easy to understand, from simple to more complex, step by step, in a very clear way. This is how education should be done. Spending months in some school learning nothing, or watching your 30 minutes video to learn actual stuff!

[@linuxman0]

By watching your explanation of the 3 resistors, I think I figured out why we use 5V and 3.3V.

[@nerijusvilcinskas7851]

I graduated in electronics engineering last year. With no luck in finding job. These videos are so interesting, latches and flip-flops are so easy! I mean in uni it was so hard to get these concepts and you are much better at explaining things.

[@robinharris4706]

I've watched a few tutorials on the 555 and I agree with another comment - this is by far the best. Extremely clear explanation - you have a rare ability to speak without hesitation or repetition. The video quality is crisp and everything is easy to see - even small details. Excellent. Please make more tutorials!

[@FarmingwithZana101]

No matter how long this video is I completely understood about 555 timer I’m really grateful and thankful to this guy

[@chrisbroome]

By far the best explanation of the 555 timer I've seen. Specifically, the layout of the diagram makes it easy to see how the charge builds up to set the S, then the R, and then finally toggle between them.

[@christianniemeijer97]

Dude, I've been watching your videos for some months now and finally I made my own clock using the kit. Next up I will be building the whole computer! Thanks for sharing, it is an invaluable piece of knowledge that you are sharing with us computer science fanatics

[@lewishbutler]

The best explanation of a 555 ever. Now I want to build a breadboard computer using these tutorials. Thanks. Still useful in 2017

[@Aemilindore]

What a wonderful video. The way you demonstrate power supply impendance. We shoid teach this at university this way

[@igoryudnikov6198]

Salut from Russia. When I was a student, our old teacher of computer architecture told us, that he don't knows anything about it. He had performed some diagrams in some software circuit cad system, and told us to learn assembly language by ourselves. Sins that I do not understand how computer works. Thank you for you videos, I hope to fill the gap in my knowledge.

[@zealphanerd1]

I have never had a 555 timer explained to me so well. I understand this 100% now. Thank You for that!

[@rohros1988]

No other channel or institution had done this type of clear n precise explanation that clears concept within few minutes...great work n great channel....

[@BirdYoumans]

My friend, I have watched literally hours of 555 "instructional" videos, I know, I need to get a life, but I also know that once I thoroughly understand something, it's much easier to be creative with it. And in fairness to the others who made vids, some better than others, I'm sure the info is somewhat collective so I know a little of how this works, but I just learned more about this chip in 30 minutes than all the others combined. Your clarity is astonishing. Wish I had found yours first since that would have saved me a ton of time. If I have any wishes tho, I'd like to have seen on the schematic exactly where the pins to the pot and 1k resistor went. I'm sure a few minutes at my bread board and I can figure it out tho. But otherwise, I fully understood everything you explained. Thank you! I feel some binge watching coming on lol!

[@ytytiuiu2590]

I don't know if you could see this or not, but my only advice to you if want to create something is take break, and try experience with knowledge you have .

[@rexor8527]

i know right! I myself am going into a field of IT i dont think can get much further than this, the closest I've ever gotten to this was a build it yourself toy wire maze thing that beeps if you touch the hook to the wire, so I know next to nothing about this stuff really, and yet something about the way he explains things is just so genuine and so complete that it just keeps drawing me back. A real shift from the "this works like this, that works like that, plug this from one into that from another and it will do this because that's how it works" feeling you get from many instructional videos, or even schools.

[@steventhehistorian]

Your videos are both enlightening and humbling. You break things down so well. Then I think about the fact that I'm using 100% of my brain power and struggling to understand a 555 chip... There's no way I could ever be an engineer.

[@jimedgar6789]

WOW! I have been using these things forever using the formula thinking there were elves inside doing all this shit. The impedance fix was something I have done but not knowing why! No wonder my stuff always blows up! SUBBED and sending you a Red Lexus Roadster!

[@TheSunriseAnimation]

Or gnomes and they come out and complain when the sand for their hourglass runs out.

[@douglasthomson2986]

It is to your credit that you've spent all this time to explain how you've built your 8-bit computer. That is no easy task. You deserve way more than just great comments. Thank you for taking the time to explain this complex area so well. Very well done Ben.

[@jeromethiel4323]

The 555 timer was celebrated as a seminal development in integrated circuit design. Just like the 741 op amp, they are ubiquitous because the basic design was just that darn good. Also in that class in the 16550 UART. Some designs are just so good they transcend time.

[@BangMaster96]

God this is just gold. You are explaining these concepts so well and clearly. I wish College Professors would learn from you, and explain things like you do. It's so rare to find a good teacher these days. Everything is left on the students to figure out on their own.

[@kirillazarov6865]

We have this, and some people will still prefer to watch the news. It's a crazy world we live in.

[@krswar]

i’ve been working on using this ic for 2 years, still couldn’t really understand how this ic works. but this vid has given me the best understanding about this ic so far. great explanation for beginner!

[@DavidRTribble]

Note that the coefficient 0.693 is ln(2), or the natural log (base e) of 2.

[@stevengreen4034]

Best instructional video series I have ever encountered. As a reductionist by nature I appreciate starting at the ground level and building upon the basics. it is the only way to truly understand. Thank you.

[@TheQWERTY173]

I am finishing up a digital logic class and wish I would have had your videos. I will definitely be using them to study for the final!

[@NorthbyWest]

As a novice, I am playing with the 555 for some toy projects for the kids, but I never knew about the 'magic inside'. Outstanding explanation. Subscribed in order to follow more.

[@MrTrumanPurnell]

BEN THESE VIDEOS ARE INCREDIBLE!!! SO THOROUGH ! NEVER STOP !

[@tuzztech6824]

I built the circuit on my breadboard and was following along with the video. I couldn't understand why my LED was flashing twice as fast as Ben's thinking it might be the tolerances on my resistors or capacitor - only to discover Ben's capacitors were 2 micro farads. Everything makes sense now.

[@sebastiantroue6320]

1 mFd means 1 micro Farad double☝️

[@laughlinmccooey8575]

Can't tell if this is legit or a joke...

[@anythingandeverything264]

@@laughlinmccooey8575 its a joke theyre probably cheap +/-100% caps

[@notserpmale03]

Just Cause THANK YOU

[@nipz8053]

That's what threw me off looking at that component.

[@momoura5]

I've struggled to understand how the 555's astable mode works, but this video gave me a perfectly clear explanation. Thank you so much for the walkthrough.

[@8bits59]

Those capacitors, judging by the "MFD" unit label, are older than dirt and have become electrically leaky, hence the high reading. Allow me to explain. Imagine an ideal capacitor. Two plates, with a gap. No DC current will flow through them once the field is built up. Non-ideal capacitors have a characteristic called leakage current, which is the amount of expected DC current flow between the plates due to things like electrolyte conductivity, ionization and metal migration over time under the force of the electric field, etc. As some types of capacitors like electrolytics and the old paper and wax capacitors age, they leak more and more DC current across that they shouldn't, and slowly start to build a parasitic resistance that decreases as the capacitor ages. Since the parasitic resistance is in effect in parallel with the capacitor (because the leakage current occurs between the plates) it causes the capacitor to take longer to charge. Most multimeters read capacitance by passing a small, known current between the leads and then sampling the voltage over a specified time (basing the reading on the fact that larger capacitors take longer to reach any given voltage at a constant current), meaning that any leakage between the plates of the capacitor will cause the reading to look high because of the parasitic current draw keeping the voltage down. Slap one of those capacitors between the leads of an old capacitor leakage tester and see how badly they leak. Some of the older caps I've seen can leak current at a charge as low as 2-3 volts. No doubt those are the same.

[@epiendless1128]

Indeed. It would be interesting to find out if the capacitor was equally inaccurate at higher charge currents, and whether the electrolyte barrier would reform over time if the capacitor was kept in constant use. As I'm sure you know, the electrolyte itself is conductive, but passing current though it forms a thin insulating layer of oxide on one of the capacitor plates, and this thin layer is what makes it a capacitor (and indeed a _polarised_ capacitor).

[@pwkoert6594]

That tels me that we measure the load time of the capacitor, I usually measure UN-load time, with the opposite result of course (many of my parts are 20jrs+) Because my first 5 555 experiments went wrong, I did not think much of if, now I am gonna try again... thanks to Ben and all use full comments.

[@edwardvermillion8807]

and here i am thinking 'mfd' just stood for 'mf' doubled...

[@kgdatasolutions8130]

I would have seen at least 6-7 videos about IC 555 and this is the best , with utmost clarity . Thank you sir

[@bluekeybo]

love your videos. I'm an electrical engineer and just found out about your computer project. awesome!

[@ki4dbk]

The way you work from datasheet to pinout, to perfboard to working circuitry is ideal for rapid learning, plus lends itself well to visualization and understanding. Inspirational!

[@thomasesr]

with the 5k, 5k, 5k resistors inside. They would either call the chip the 555 or the KKK... I Guess they preferred de 555 for some reason...

[@DavidTangye]

Thomas Richter it is not called a 555 because of the resistors. That is just a coincidence.

[@aidanfransen3571]

its not a coincidence...

[@petr_e]

That's a common mistake. There's no sense behind 555's name. Here you're able to read an interview with Hans Camenzind (an author of the scheme) about the name www.quora.com/Why-is-IC-555-called-555-Why-not-111-or-any-name

[@kurtisodonnell321]

Yep its coincidence, that is (from memory) the 555th IC they made

[@petr_e]

Oh, man... Just a cite from Hans Camenzind (an author of the scheme): "Signetics had “500” numbers, and the earlier product I worked on was the 565, 566 and 567. It was just arbitrarily chosen. It was Art Fury (Marketing Manager) who thought the circuit was gonna sell big who picked the name “555”"

[@arthurfricchione8119]

Very well explained video. I’m new to electronics ( retired aircraft mechanic in the real world) but am now diving into this field and trying to teach myself from the bottom floor and working my way up and your videos are excellent. Thanks for sharing Artie 👍👍👍

[@rustyz4014]

Change the LED to a relay and a motor, and you have the circuit for the delayed wipers on your car. Nice job.

[@skilz8098]

Or just plug it into to the turn signal regulator, but you might want to slow the pulse down just a little bit...

[@Engineer9736]

I don’t think the 555’s output is able to deliver enough current to trigger a turn signal relay. Even if it’s able to do so for a while, it will become quite hot.You’ll need to add a big transistor in between or a FET.

[@juliet0001]

@@Engineer9736 no, you would use the turn signal clicker instead of the 555

[@viveksinghal1108]

Can you use a voltage follower to get the extra current?

[@Multibe150]

@@Engineer9736 What about an optocoupler? Or even a relay-optocoupler combo

[@tensor131]

FINALLY ... I understand this circuit !!! Seen so many authors attempt to explain this but always fell short on detail, leaving me confused. YOU SIR have done an impressive job here - I now understand everything, Thank you .. subscribed

[@adnamamedia]

a really fun project would be building a 555 without integrated circuits

[@pewnit]

As a computer engineering student, this is Gold. Thank you. I was always curious about how the 555 works and now I've got it.

[@power-max]

The tolerance of electrolytic capacitors can be quite bad! Like, +-80% bad! Those could very well be within tolerance!!! :O

[@ThinkinThoed]

Just purchased the complete 8-bit breadboard computer kit, and starting to re-watch the series while I wait for my shipment. :) Thank you for your time and expertise in assembling this kit/video series, greatly appreciated!

[@Blinkation]

Finally! I get it now, thank you very much.

[@GothPanda]

I normally don't comment, but I had to say that this is the first time that I've ever actually understood how the heck a voltage divider works. So, thanks for that.

[@Penfold8]

I had always heard there was capacitors that show "+" on the capacitor rather that the "-" sign. This is the first time I have actually seen the "+" designation.

[@floriangassmann272]

I was so confused about why his capacitor is plugged in the wrong way round because i only payed attention when you could see the top of it...😅

[@Nick-wj5gw]

Great teachers are able to demonstrate complex ideas by not skipping over any of the simple fundamentals. This is great! Thank you Ben!

[@rj-nj3uk]

During an intro lecture to 555 timer, our professor asked "Do you know the use of 555 timer?" to the class. And everyone in class having no idea was like "maybe to make time bomb?". XD

[@Sierpina_WMG]

A repeating timer? That's not even a good answer.

[@Douglas.Kennedy]

you only need one count to trigger a device- a big capacitor and a comparator would do. don't waste an entire 555 timer! unless you need a count down timer, then you can use the 555 to generate a clock to run a counter. put the trigger on the most significant bit 😜💣

[@welshspaceagency]

This is the absolute best of the internet. Stop looking folks, it doesn't get any better than this. You are a brilliant, thorough teacher Ben.

[@ryanjl9]

Variable resistors, for when you need to overclock an 8 bit computer...

[@gettingpast4391]

This is the best explanation of how a 555 timer works (internally) that I have ever seen. I was wading thru breadboard computer builds, and this video alone was enough to make me subscribe. So far every single video in this playlist has been JUST AS GOOD... everything explained perfectly. Subscribed! THANK YOU!

[@Mark-id7uy]

are you pointing with a piece of uncooked spaghetti?

[@RoboGenesHimanshuVerma]

😂Its just single core wire with the sheils on though

[@toma5153]

You're videos are perfect for the middle school or high school kid who wants to learn some basic electronics. With some budget assist from mom and dad for the basics plus instruments. You could get by with a used scope off of Craigslist. Just a huge amount that can be learned. I compare it with my own experience as a 13 year old, got my General amateur license at 13, fiddled with dangerous vacuum tube circuits. My dad was Navy vet w radio experience. He encouraged a lot.

[@musicbyvec1955]

At first I thought he was pointing with a dry spaghetti

[@oussamaelhriki8160]

😂😂😂😂😂

[@ilustrado7291]

Did you see vomit on his sweater already?

[@maleknecibi]

Ilustrado - Well on the surface he looks calm and ready, but maybe he's actually nervous

[@joekanaan2548]

@@maleknecibi but he keeps forgetting what he wrote down

[@smacman68]

How has this evaded my recommended for 7 friggin' years? So good.

[@Captaincodeine]

.693 is log(0.5) and is the half decay constant. I'll never forget it because it was in Feynmans book

[@DantevanGemert]

Actually, it is -ln(0.5), which is the same as ln(2)

[@Captaincodeine]

@@DantevanGemert you're right.

[@dru6809]

Which book?

[@OliverJensen5115]

About halfway through this video -- after having gone through the 65c02 playlist a few months ago -- I had a bona-fide Eureka moment. I finally understood why overclocking your computer too far causes it to malfunction, even if it does not overheat. And also what overclocking means on a fundamental level. Didn't think I'd experience that when I clicked this video :)

[@micahcowan]

For novices like me: note that while you'll want the electrolytic (cylindrical) capacitor's white stripe on the (-) side, in the video it's on the (+) side. Your capacitor polarity should NOT look like his, for some reason he's got one where the + is striped instead of the - (which you can confirm when he takes a closer look to figure out why it's 2uF). Also, in ceramic capacitors in the video, the 0.1uF one looks wider than the 0.01uF one (which makes intuitive sense to me), but in the kit it's the reverse (which had me second-guessing myself). Don't let the size concern you: 104 is 0.1uF, 103 is 0.01uF, end of story. If you're fairly inexperienced with electronics (like me), go read or watch some stuff that ensures you understand how to read the components (especially the resistors, the ceramic capacitor, and the polarity of an electrolytic capacitor). I knew to refresh myself on these things, and got everything right on my first attempt; but I was heavily doubting myself until I switched on, because the components in the kit and the components in the video were very different! Also if you're reading this before you've gotten to the later videos, be advised that the part 3 video is WRONG for this kit (the switch will still work, but it WON'T be de-bounced - the video is using a break-then-make switch, but the kit has a make-then-break, and that very much matters). Look for a comment by Sergey that sets you straight on the simple but necessary modifications (reversing the logic). You can follow the video, confirm that it doesn't work when you very slowly slide the switch, and then make Sergey's modifications if you like - it won't hurt anything.

[@mSchwippy]

I was taking an online course at work kinda related to computer stuff and my googling about deeper ideas of how computers work at a base level brought me here. The amount I dont know or understand about anything being said even 60seconds in is completely humbling even though I use these devices everyday

[@michaelhamor6113]

Silly question. I've been working my way through Make:Electronics. Chapter 11 has you build an circuit out of resistors, capacitors and transistors gives and alternating on off signal with a nice square form. Frequency can get very high and seems stable. Could you use that as the computer clock instead? What draw backs would there be compared to this setup or even a quartz clock setup?

[@iainwilliamwiseman4602]

New to electronics, had a stroke and decided to start my journey from IT/PM background. Watched tons of theory on Capacitors, Resistors, gates etc was wondering what it was all for. This was a great video showing what I can do with it. Thanks.

[@patprop74]

great explanation and your drawing does make it easier to understand, I am somewhat new to electronics, I know the 555 is rather cheap in price, so what the difference between using the 555 as a clock or to blink a led, compared to using a npn transistor and a cap? which is a lot cheaper.

[@JanicekTrnecka]

Dick Fageroni In fact you can, but its pretty nasty solution. Avalanche effect in trsnsistor makes it conductive, dischsrges a cap and the cycle repeats. But the edges of such clock are nasty snd it has a pretty nasty voltage spikes.

[@AshishVerma_Awesome]

even after 5 years of this video upload i have never found video better than ben eater explaining ne555 and many logic gates Sal khan and ben eater huge respect for u both

[@sikor02]

This is gold

[@RMD1423]

I'm mechanical engineer and try to learn electronics and your channel is quite helpful

[@deltakid0]

awesome!!!! thank you for this!!!

[@maxpolaris99]

Fantastic explanation of the 555 astable operation. I still have a 555 I bought @RS about 40 years ago. It still works. I've been out of Tech School 30 years. I'm taking notes. Thank you.

[@zeusnitch]

12:03 "Doodie cycle" All I can think of is Catbug laughing.

[@63801170]

I'm late to the party, and have really never understood how the bits work (ie. don't know about electronics, other than all the pieces make a circuit), but now you've explained pieces of the puzzle that make sense to me. Like the part where you said the flow through bother resistors and then back, was so simple to understand (for calculations, etc). Thanks. 👍

[@47Mortuus]

Ben Eater: "We can pull out a calculator here..." Phone: "Am I a joke to you?"

[@nikyesify]

Such a thorough explanation. Not only the explanation but the analysis on the scope made it so much more clearer to have an in depth understanding.