How a 555 Works as a Timer.

In this video I explain the building blocks of a 555 chip and how it interacts with the components you connect around it to become a “Timer”!
I talk through each stage of the 555 including
- Voltage Divider (comprising of three 5K resistors)
- Two Comparators
- The Flip-Flop
- NPN and PNP Transistors utilised for Discharge and Reset
We explore the Charge and Discharge times as the capacitor oscillates between the 1/3rd and 2/3rd voltage levels and verify that with an oscilloscope.
If you are interested in the handy configurable Resistor boards I utilised you can purchase them from Amazon here:-
amzn.to/3RYiX75
For more information about Voltage Dividers, see one of my previous videos here:-
• What Are Voltage Divid...
Timeline
-----------
00:00:00 - Introduction
00:00:59 - PKAE Electronics Intro Theme
00:01:09 - Internal Stages starting with Voltage Divider
00:02:29 - Two Comparators
00:04:16 - Control Voltage Pin
00:04:32 - Flip-Flop & Output Driver Stage
00:05:40 - SR Flip-Flop Explained
00:07:27 - NPN Discharge Transistor
00:07:50 - PNP Transistor for External Reset
00:08:14 - Summary of Stages
00:08:39 - Comparator/Flip-Flip Experimenting (Theory)
00:15:54 - Comparator/Flip-Flip Experimenting (Bench Testing)
00:17:58 - Astable Circuitry - External Capacitor and Two Resistors
00:21:20 - Bench Testing Astable Mode
00:22:48 - Datasheet Astable Circuit Diagram
00:23:27 - Control Voltage Capacitor (Stability)
00:23:53 - Timing Calculations (On and Off Times)
00:25:41 - Bench Testing Timings with Oscilloscope
00:29:06 - Timing Summing Up
00:29:17 - Frequency Calculation
00:30:12 - Wrap Up.

[@dougtaylor7724]

Back years ago when I taught myself electronics I bought one of the multi purpose board kits you can use to make 200 or so projects. When I played with a 555 that was the most amazing chips ever. Make timers to turn on and off at different times.! Once made a timer that took a month to turn on. After calculating the resistance and caps it was put in the living room and did nothing. Just sat there waiting to trip on. The wife thought I lost my mind. One Saturday about 4pm it came on. The timing was about 6 hours different from what I calculated. But, it was amazing a $1 circuit went off that close after 32 days. And I made it do that! The wife really thought I had lost it then. 😂

[@paulpkae]

Haha! Brilliant! that made me laugh, thank you.

[@jasonbender2459]

Your timer was 99.24% accurate. Well done. Your wife does not deserve you.

[@jagmarc]

@@dougtaylor7724 In the late 70s a colleague did a industrial controls dosing pump driver which used a simple RC timer with insane long period and being inexperienced, he didn't realise after it left assembly line no one in Functional Test wanted to wait a week ten days whatever it was. So the boss had to change the timer to something actually measurable and added a CMOS divider IC patched under PCB. We called the guy The 555 Kid after that.

[@Mike-H_UK]

It is normally not a good idea to try and make very long delays (say greater than an hour) with a 555 directly because leakage in the capacitor tends to dominate the operation at such low charging & discharging currents, and the circuit is very sensitive to noise close to the comparator trip points. Adding a divider (as also suggested) makes operation much more dependable. Still, I had great fun s a kid learning these things for myself!!!

[@Patrik6920]

Fantastic... ya u can do all kinds of fun stuff with just a very few chips...

[@Enderbro3300]

PLEASE I am BEGGING explain op amps like this. I feel like a BARELY understand them and this video made me feel like I can explain a 555 to a toddler!!

[@paulpkae]

Hi. Yes, an Op-Amp explanation will be essential content for my General Electronics collection. It is on my long list to do.

[@JamesHarr]

I think this is an excellent explanation of op amps, at least when they don't have any direct feedback loops. Op amps get weird (and interesting) when there is a feedback loop involved. I can't remember who explained it or even the specific circuit configuration, but when the feedback loop is involved, "the opamp will do as much as it can to equalize the input voltages" and that's what stuck with me. I look forward to Paul's explanation of opamps because I think it'll be even more clear than that.

[@paulpkae]

@@JamesHarr challenge accepted 😲

[@JohnDoe-lg8dr]

@@JamesHarrThe way that I learned op amps was that the op amp has variable gain internally and through magic will change the output voltage to make the two inputs equal. Then assuming the two equal inputs, you can find the desired output voltage. Slap on a capacitor or inductor and you now have an integrator or differentiator

[@diverbob8]

Excellent Suggestion....Op-Amps are analog devices, so they can be amplifiers, and used in combinations, they do so much more.

[@MrThedennisblack]

It’s exactly this kind of thing that we dreamed the internet would do for us - let people freely share their talents and knowledge with each other. Great explanation and video! Taking the time to briefly explain how the comparators worked and how the flip-flop worked is the exact kind of thing someone who doesn’t have natural teaching ability would have skipped completely.

[@jaykoerner]

You just have to wade through the ai generated fake videos, completely lose your privacy to multiple gigantic corporations and be completely unsure if your even talking to a real person since 25% of Internet traffic is scammy bots and another 25 is supposed good bots

[@paulpkae]

Thanks. I find sharing knowledge to be very rewarding. All your comments make the effort all worthwhile.

[@arosnett]

Word!

[@newmonengineering]

This is the best explained 555 timer video ever. I understand what it does already high level and how to figure out the numbers but I have never seen all the internals so completely discussed and stepped through like you did. Brilliant work! Absolutely love electronics so throughly explained with real world results like this. Keep it up! And thank you for a more indepth understanding.

[@paulpkae]

Many thanks for your great comment.

[@qlue7881]

I agree I've been doing electronics as a hobby since the late '80s and read many articles on this IC Today I understood, for the first time, why a 555 can't give perfectly symmetrical square waves

[@paulpkae]

@@qlue7881 thanks for the comment. A video on how to achieve 50% (or higher) duty cycle is coming, if that's what you mean.

[@paidaki11]

😊😊👍👍🙇🙇🙇🙇🙍🏾‍♂️❤😅❤❤😮

[@brainforest88]

I am 61 an I am used the chip when I was 17. Didn‘t know this chip is still around. Nice!

[@c1ph3rpunk]

It’s still all over the place.

[@paulpkae]

Still going strong and now manufactured by many companies and in various form factors, TTL, CMOS. There's even a dual 555, namely the 556.

[@rfymf]

60 y. o. here... same. Designed and built a digital clock around it at 15. With the additional 74something nand gate ttl chips, it had the accuracy of 1 min per hour, and drained C batteries in a couple of hours...

[@numbr6]

Of course it is still around! I've got a bunch of them in my drawer of digital chips, along with my TTL and CMOS series chips. I first started tinkering with this chip from the TTL Cookbook, author Forrest Mims published by Tandy/Radio Shack. I've still got my copy of that book along with a bunch of chip pack cardboard "data sheets" stapled to the inside cover of of this book. Back in the 70s/80s, getting data on chips was hard. You kept those precious package data backs, and was very familiar with the Reader's Guide to Periodic Literature, and microfiche film at libraries to get data. Now it is just a Google search away, or a visit to Digikey! Technology has made some things easier.

[@ezemeza1363]

I am 31 and getting started into electronics. This chip is very useful and cheaper than programming and Arduino

[@karlsangree4679]

This might well be the best explanation of an electronic component I have ever seen. This is "Electronics for Dummies" which is exactly what I need. I just went to his main page hoping and praying that he had a complete "Learning Electronics" tutorial but alas...😥

[@robr4662]

More like electronics for someone who is casually familiar with how electricity works. If someone was truely uneducated about any electrical theory, this video would be useless. That being said, this video explaining a 555 timer is better than any other video I have seen on the subject.

[@paulpkae]

Hi thanks for the comment. My channel is quite new and small at the moment, but I have much bigger plans for it. and any more videos will be coming. Please make sure you Subscribe if you want to support. Thank you.

[@paulpkae]

@@robr4662 thank you.

[@JohnVance]

@@paulpkaeSubscribed, thank you!!

[@katelikesrectangles]

this is the first time this chip has ever made sense to me, i never understood what it was doing inside. it was always explained to me as how to *use* it, not how it *works*. thank you so much!!

[@paulpkae]

That's Great! More videos on the 555 coming, so make sure you Subscribe. 😀

[@katelikesrectangles]

@@paulpkae oh this was an insta-subscribe for me, you've solved something that's been a mystery at the back of my mind since the '90s, where i felt like it was just my fault for not getting it. and i just never realised it could actually make sense

[@AnarchistArtificer]

I have very little experience in electronics, so no idea why the algorithm offered me this video, but I watched the whole thing, learned a bunch and thoroughly enjoyed myself. That says a lot about the accessibility of this video

[@paulpkae]

Wow, thanks!

[@Argoon1981]

Almost the same here, I add seen videos about this subject before but not a electronics guy my self and I did learned a bunch with this one, even thou I don't think I will ever use this knowhow, at lest it demystifies computer tech to me.

[@AnimationGoneWrong]

I have to say this is THE most well done, clearly explained explanation of a 555's operation I have ever seen... and I've seen a LOT! I especially liked how you showed the actual charge/discharge of the capacitor on your 'scope. Nice touch! It's nice to see you explain that, on it's own, the chip is NOT a timer at all... it requires external components to become one. I had also heard that the designation (555) came from the 3 5K resistors in the voltage divider chain. I hope whoever invented this wonderful chip got some HUGE recognition for it. It has probably had the longest useful life of any chip on the planet! Over 50 years!!!

[@paulpkae]

Thanks for the comment, much appreciated.

[@billdevany3303]

your addition of the color gradients was a real game changer for me. thanks for this. Well done!

[@paulpkae]

Thanks. An additional bit of effort can make a lot of difference.

[@YodaWhat]

It is worth mentioning that the Control Voltage *pin, #5, is also known as the Pulse Width Modulation pin.* I have had great fun playing with that function, even turning a CMOS 555 into a Digitial Mode audio amplifier with pin 5 as the audio input! A couple of extra components are needed beyond the usual few for a simple timer: an external transistor to make the duty cycle 50% ON and 50% OFF, plus an inductor to knock out the high frequency elements of the output signal, and a small capacitor on pin 5 to give DC isolation from the audio source. I set the oscillation frequency to be 2 MHz, which is only possible with the CMOS 555. That meant each wave of the audio input was _in effect_ 'sampled' 100 times (for 20 kHz audio), and 100,000 times (for 20 Hz audio), giving high fidelity to the *_implicit_** A-to-D conversion* and to the audio output. 🙂

[@paulpkae]

Thanks for sharing your knowledge.

[@KatyInesSB]

Never see a video about 555 well explain. Amazing. Keep me on screen to understand this chip, and how they work.

[@paulpkae]

Glad it was helpful!

[@jeffspaulding9834]

People say it wasn't named after the 5K resistors because that's what the inventor of the 555 said in an interview. It was named by a marketing fellow who thought "555" was catchy. Brilliant video, BTW.

[@paulpkae]

Yes, I have heard that too, but for me it seems too co-incidental. Thanks for the comment.

[@matousejem]

Maybe the marketing fellow saw the schema and got the idea.

[@peircedan]

@@paulpkae You may think it is too coincidental but it don't know any reason to think it is not a simple coincidence. Historically there was no logic for how these early ICs got their number designations. As far as I know it was generally mostly chance. The 556 is essentially two 555s in a single package. There is no difference in the resistor voltage divider. I don't recall hearing anyone speculating where the name came from back in the 70s or early 80s. No one questioned where 7404 got that designation either. Engineers just like to number things.

[@techtopics5782]

this is honestly the best explanation I have seen on the 555 and its operation. The explanation + visuals + calculations + breadboard + scope with comparison = awesome. I like that math!

[@paulpkae]

@@techtopics5782 thanks.

[@athousandprojects]

I think this is the best video about how a 555 works I've ever seen.

[@paulpkae]

Thanks so much.

[@gedtoon6451]

Great in-depth video on the 555 in astable mode. A follow up video could cover monostable mode. This would explain why the designer of the device didn't just connect trigger and threshold together inside the chip.

[@paulpkae]

Thanks for your comment. I do intend doing some follow up videos to this. My very next video however is going to be a review of a nifty digital microscope.

[@tlum4081]

i once worked for a small company whose main "electrical engineer" only knew relay ladder logic. I designed a simple 555 circuit operating in a sequence to signal solenoid air valves to open to blow dust from a multiple dust bag system into the waste bin. Worked like a champ. They thought it was the cat's meow.

[@paulpkae]

Brilliant!😄

[@tedbastwock3810]

What an amazing video. I have watched probably 2 dozen 555 videos recently, none are better than this. Visuals are great. Was also a very good explanation. You managed to make an entertaining and informative video on something that already has a lot of videos on it but with a unique and useful twist. E.g. I never took the time to figure out exactly how the astable mode works, and I'm very glad you walked me through it here. I haven't seen anyone else do that, and I'm glad you did. I cant wait to see see your other 555 videos that you mentioned at the end. Thanks for sharing.

[@paulpkae]

Many thanks for your comment. More videos coming......

[@dustinduncan2444]

Brilliant video. I was surprised that I could watch this length of video on the venerable 555 and not find my mind wandering. It's a testament to the ability to teach and keep people engaged in the content. I really appreciate breaking down the pins and how they are related without just glossing over why a given pin is connected to a specific point in the circuit. The color coding of the internal and external voltages along with the logic level changes definitely made it easier to follow what was going on. Bonus points for building up the bench demo from a couple LEDs to the oscilloscope traces that took the diagrams from a simulation to the real world.

[@paulpkae]

Thanks for your comment. It took quite some effort to put this together to be honest, but I am please with the outcome, especially all the comments like yours. Please remember to Subscribe, if not already. 😁

[@remi3741]

like in the comments already i to never saw a video so well explaned about an electronic divice. fantastic. i wish more people would do it like this on more components or cicuits. its fantastic for biginners and hobby. thank u so much.

[@paulpkae]

thanks so much for your comment. I'm glad you found it useful.

[@MarkALong64]

That was an enjoyable trip down memory lane :) I once met a very excited chapin the gents of a Southampton pub who had designed the timer circuit for the hot air hand dryer using an NE556 and for some reason, he really wanted to explain the circuit to anyone who would listen.

[@paulpkae]

From my experience, those hand dryers must have the wrong size capacitors in them then . 😆

[@flyddw]

That was the absolute BEST explanation of the 555 chip. As a wannabe EE major in college - I gave up on the math and continuous curves and chose CompSci instead. However - if you were my teacher, I definitely would have stayed in. Brilliant!

[@paulpkae]

Fantastic! Thanks for your comment, much appreciated.

[@dingledodger5323]

I... Need you... To watch Kindergarten Cop with Arnold Schwarzenegger and watch for the lines "It's not a tumor". Then read your thumb nail. Absolute gold

[@paulpkae]

Yes, several people have commented that :)

[@shader26]

Needed a refresher course on the 555 and wow..did I get one. Excellent tutorial and graphics, hands on. Explained well and perfectly and real time experiment. Thank you!

[@paulpkae]

Thanks, glad you enjoyed. Please be sure to Subscribe. More 555 videos coming and I will be ramping up on this channel in a few months time.

[@javiermitchell7073]

Really well explained. This must have been one of the most " mysterious" circuits I came across when I was a youngster!

[@paulpkae]

Thanks. Glad you enjoyed.

[@TheRandomDave]

Adding my voice to all the others...absolutely brilliant job explaining and demonstrating the 555 timer.

[@paulpkae]

Glad you liked it!

[@user-rl5zj7np4e]

A Masterpiece for electronics engineering teaching. Bravo!!

[@paulpkae]

Wow, thanks!

[@alexcrouse]

I once found a single chip circuit board controlling the water level in a tank. Very very old system. I asked the maintenance grey beard why they had a microcontroller instead of a PLC. He laughed. "That's a 555!" With some resistor magic and a variable resistor on a float, they set the low level to report 3v, and the high level to 6v, and the 555 triggered the fill valve.

[@paulpkae]

Thanks for sharing. I'm sure there's been millions of different 555 implementation types over the years.

[@markramsell454]

I used one of these for a 1Mhz clock on a 6502 board I made. It worked just fine. Nice description, very thorough.

[@paulpkae]

Very nice!

[@Mitch3D]

Thank you for this explanation and demo! I only really learned how to do microcontrollers with electronics so finding out other uses for simpler components is useful. One use for the 555, instead of a capacitor and voltage divider, you could use a thermistor to vary the threshold voltage based on temperature and tie the output to a relay to turn on a heater, you have made a simple bang-bang control loop.

[@paulpkae]

Thanks.

[@dominicestebanrice7460]

How bizarre......there are 555 comments on this brilliant video as I post my sincere THANK YOU!

[@paulpkae]

556 now :) Thanks for the comment.

[@RexxSchneider]

The NE555 bipolar timer has an output stage that produces a significant spike of current as it switches, and that can cause problems both for itself and for nearby ics as it tends to produce a negative spike on the supply lines. It is pretty essential to place a ceramic 100nF capacitor across the supply pins, close to the ic to suppress that. It's not so necessary if a CMOS 555 is used. It doesn't matter for the astable circuit you show, but for use as a monostable, or other circuits, it's worth knowing that the TRIG input (pin 2) overrides the THRES input (pin 6), which means that if the TRIG input is held low, the output goes high and the THRES input cannot reset that by being taken high.

[@squelchtone]

As a visual learner, this helped me a lot.

[@paulpkae]

Great! Glad it helped.

[@LonnonFoster]

Brilliant explanation! It's not often I find any material that blends theory and practice so well. Your shifts between diagram, breadboard, and oscilloscope are beautifully timed in the video; this is the clearest I've ever seen a 555's operation described. Thanks for taking the time to craft such an excellent video!

[@paulpkae]

Glad you enjoyed and thanks for the great comment.

[@spark_coder]

This is by far one of the best explanations for an electronic component that I've ever seen. Your intro burst my ears (I was wearing earphones) but it was totally worth it for how good this video was and how well I was able to understand what you were teaching. Thank you for this video ❤

[@paulpkae]

Thanks. Yes a few people have mentioned the intro volume. I had tweaked by OBS settings prior to recording to try and improve the clarity and forgot to normalise my intro recording. Other than that, I'm glad you made your way through it and found it of use.

[@diverbob8]

That was fun...like you, I was there at the dawn of digital circuitry and having build dozens of 555 circuits, I immediately realized the purpose of your click bait. I congratulate you on your patience in following through the explanation of how it works. Somewhere around here is a red book with about 100 555 projects from turn signals for a motorcycle to windshield wiper auto sweep, etc. Very effective post...Great Job!

[@paulpkae]

Thanks, glad you like it.

[@karlwimheese1587]

you are a fantastic teacher! The explanation of the internal workings is brilliant.

[@paulpkae]

Thanks for the comment. Glad you liked it.

[@GrandsonofKong]

Great description and video! 555 was developed by Signetics founded by some former Fairchild Semiconductor Engineers (like Intel was). I worked at National Semiconductor (just around the corner from the Signetics Plant) and we called it the "Triple Nickel" at least in our department(Test Engineering) when NSC decided to second source the 555. Still have a Signetics Apps Book on my bookshelf and a very useful chip when the only option was a bunch of TTL Logic to do timing when you could get away with only a few external components back in the day.

[@paulpkae]

Thanks for the comment and your interesting history insight.

[@CraigsWorkshop]

Thanks for making this video! I had 3/4 of an idea how these chips worked, but now it's crystal clear. You are a great teacher. I hope you keep making these vids. Cheers!

[@paulpkae]

Thanks for watching and the comment, glad you found it useful. Yes more videos are coming, so make sure you Subscribe too 😁

[@anonamouse5917]

If only this could have been packed into a 5:55 video it would be platinum tier.

[@paulpkae]

🤣

[@fshieldsii]

First time you've shown up in my feed. Your explanations and presentations are so good that I've subscribed!

[@paulpkae]

Brilliant! Thanks for subscribing.

[@AvastAntiPony9445]

Ok now it makes tenfold more sense to me why it's called a 555, genuine surprised i haven't heard anyone explain it till now, and that everyone calls it a "timer" chip.

[@rv6amark]

Well done. Good graphics, good explanation. Every time I work with a 555, I have to relearn how it works. Now I know where to go for that information.

[@paulpkae]

Thanks 👍

[@mal2ksc]

I read the thumbnail in Arnold Schwarzenegger's voice, like the line "it's not a tumor". 🤣

[@paulpkae]

You're not the first to say that. :)

[@donkeymedic]

This is by far the best explanation of the 555. I struggled to understand it , but this made it clear.

[@paulpkae]

Thanks for the comment, much appreciated.

[@jensschroder8214]

On the NE555, the reset input always overwrites the set input. On the B555, the set input overwrites the reset input. The replica wasn't quite perfect. This only happens when pin 2 is low and pin 6 is high at the same time. So comparator 1 and 2 are high at the same time. But for most circuits it makes no difference, because pin 2 and 6 are mostly connected. Therefore both comparators are different or both low. With the B555 the /Q output of the flip-flop is not used but the Q output. That's why set is stronger than reset. Accordingly, the output driver is not inverting.

[@dennisbuns]

Enjoyed the whole video. I had learned about 555 before but this is much clearer and easier to remember. Keep doing this please. Cheers.

[@jerrywright9657]

In 1980 I used a thermistor in the timing circuit to produce a temperature sensitive pulse duration. That pulsed a milliwatt CW transmitter so I could remotely get temp data by monitoring time between pulses. That got implanted in free ranging woodchucks so we could monitor location and hibernation status.

[@robandsharonseddon-smith5216]

Loved it. Took me back to my teens in the 80s. I never understood it then tho. More like this please

[@paulpkae]

Thanks for the comment. More videos coming....

[@craxd1]

A good lesson for electronic students on solid state logic. Well done. When I went through school, everything was shown on a blackboard.

[@paulpkae]

Thanks for the comment,

[@mistaecco]

I've never stuck through with properly learning electronics on this level, but have found reasons to solder and build anyway. This was brilliant. Perhaps I'll end up brushing off one of my kits!

[@paulpkae]

Glad you liked and thanks for the comment.

[@gunblad3]

Where were you when we were learning circuits…. Thanks! Enjoyed learning what they should have taught us

[@paulpkae]

Glad you enjoyed it!

[@SusanAmberBruce]

You put a lot of effort into this video, thanks, I hope you are not discouraged by the lack of interest

[@paulpkae]

Thanks. It was indeed a lot of effort. I just hope people enjoy the results. Thanks again for your comments, much appreciated.

[@tedbastwock3810]

Lack of interest? You commented 3 hours after it was published. Give it time, Im sure this vid will get a lot of views .. or at least it should, considering how good it is.

[@esra_erimez]

@@tedbastwock3810 I could not have said it better myself. This is by far the best explanation. I think this video will go viral

[@peterwadham7965]

I agree this is one of the best explained 555 timers vides that I have seen, I remember looking at the timer at college and it seem difficult to understand as we had was the RS data sheet written by electronic professors

[@paulpkae]

Thanks. Brilliant comment, encourages me to produce more....

[@int2str]

Wonderful video - thank you! Best explanation of a 555 I've ever seen. Really helpful!

[@paulpkae]

Thanks, much appreciated.

[@jeromewelch7409]

So I guess it's safe to say 555 is a sequencer used in timing …. Awesome video

[@paulpkae]

Thanks for the comment.

[@hankcohen3419]

Brilliant! It makes me admire the engineer who thought this up in the early days of digital electronics. Also confirms that all electronics is analog.

[@paulpkae]

Thanks for the comment. Yes all electronics can be said to be analogue. A 1 or 0 is only a voltage threshold at the end of the day. Just to add, from my experience, everything also always boils down to Ohms law if you drill down enough.

[@joedfazio]

I designed circuits using 555 timers back in the late 80’s. Thanks for the memories! BTW the 556 is twice the fun 😊

[@paulpkae]

Thanks, glad you enjoyed it.

[@arthurmoore9488]

Commenting before I watch the video. Bet it's going to be how the 555 is really a dual comparator with some nifty tricks. The "timer" bit comes from how long it takes to charge/discharge a capacitor to a specific value. It's been years since I've worked with one though, so this is pure memory and speculation. I should also note that using similar circuits, you can measure voltage by using it as a voltage to frequency converter, then measuring the frequency. With the beautiful part being the final measurement circuitry can be optically isolated!

[@thb40]

excellent explanation of how the 555 works.

[@paulpkae]

Thanks! 👍

[@zalida100]

Excellent vid. Clear explanation etc. Very enjoyable. 1st class stuff. Thanks for your efforts.

[@paulpkae]

Glad you enjoyed it and thanks for the comment.

[@KonstantinDeak]

First video I've seen of yours and its great. Very clean, no blurry camera stuff, WELL explained, excellent format of diagrams and bench testing. Liked and Subscribed!

[@paulpkae]

Awesome, thank you!

[@BoukeGroenescheij]

Wauw, even though there are over 300 reactions telling you this is the best explanation ever seen, I'll just add another one. What a great explanation, one of the best 30 minutes on KZbin :-). Thank you for sharing, I've subscribed!

[@paulpkae]

Great! Thanks for watching, the comment and even more for Subscribing.

[@connecticutaggie]

Nice explanation of how a 555 works.

[@paulpkae]

Thanks for the comment.

[@odbo_One]

This is the first IC I grew up learning. It all took off from there, good times. I may relive that. I still have at least 10x 555 and 10x 556 IC.

[@tsbrownie]

Really excellent video and description. Thank you!

[@paulpkae]

Thanks, glad you enjoyed.

[@user-vs9oq8cd8l]

I remember back in the 70's with my father in his ham shack bread boarding a nixie tube light sequencer based around a 555. Thanx for the memory.

[@paulpkae]

Great stuff!

[@Plumpkatt1]

Although my mind is mush watching this video I actually really understand it the way you explained it at the end. I just stumbled across the video and it seemed interesting especially the way you explain. I love seeing your real world example after your lecture because it lets me see it in action which I need to be able to get an understanding.

[@paulpkae]

Glad it was helpful!

[@Electrodoc1968]

Nice to hear this explanation lives on.. PNP & NPN Was one of the first things I was taught when I was in a YTS T.V. Engineer training apprentice. ~1986 + Point iN Please & Not Pointing iN. Project building hobby led to a self taught knowledge of the voltage polarity workings for basic switch amplification. ie. PNP = A Positive on the Emitter then the base should be held Negative 0v to switch the collector through to the Positive. NPN = A Negative on the Emitter then the base should be held Positive to switch the collector through to the Negative. Basic relay type stuff. But also a general rule in amplifiers but that gets more datasheet reliant for HFE values etc. Cheers.

[@paulpkae]

Thanks for the comment.

[@JohnVance]

I finished Ben Eater's 8-bit CPU and wanted an even more in-depth explanation for the timer, and your video was fantastic. Also had no idea those jumpered resistor network boards existed!

[@paulpkae]

Wow, that must have been a rewarding project to have completed. I have watched Ben's videos too and fascinated in seeing the building blocks of a computer assembled and running on breadboards.

[@MrHyde-wv8wi]

The Good old 555. Big thumbs Up.

[@MKeuning01]

Absolutely wonderful explanation of the 555. Thank you.

[@paulpkae]

Thanks. Glad you enjoyed.

[@eitherrideordie]

Absolutely lovely video! I always wondered how it worked and the explation was so easy to follow. It was fun to follow along because it made me think in a way that me realise the timing answer before you reached it. Cheers!

[@paulpkae]

Brilliant, thanks for the comment.

[@grahamlewis6777]

Great video, thanks for all the effort you put in to create this with all the graphics too. Great work :)

[@paulpkae]

Thanks for the comment, much appreciated.

[@jupa7166]

It is a brilliant chip design, sooooo versatile! I like it very much. I also like LM10 - look it up, the datasheet just oozes with ideas.

[@GregOnSummit]

Man ... this is what I like. Easy to understand with a nice example on what you did. Subscribed 👍

[@paulpkae]

Awesome, thank you!

[@muhammadhussain7976]

Very impressive demonstration and explanation!

[@paulpkae]

Thank you.

[@eekee6034]

The 555 is a funky bit of kit. :) It was perhaps the first chip to make designing timers and oscillators easier, but it worked out so well, it's still around. I once designed a FSK encoder using a 555, only in simulation, but it was really easy. The digital data went through a 2k resistor to the control voltage input, but that was given a source with no internal resistance. If I ever build a retrocomputer, I'll probably build that circuit for real because I think retrocomputers have got to save data to tape. ;) I probably won't use it very much though, I don't miss 5 minute load times!

[@paulpkae]

Thanks for the comment. From my experience it was often a load time of 5minutes or more and then it failed anyway.

[@eekee6034]

@@paulpkae Yeah... my first Atari had some weird problems with the tape drive and the ZX81 would fail for all sorts of reasons.

[@mazeppa8818]

Thank you for this educational video! Really like the idea of colour-coding the voltage values!

[@paulpkae]

Thanks. Yes colour code t represent the voltage (or potential) I think helps a lot. Pleased you found it useful.

[@Ancipital_]

Thanks, I will need to watch this a couple more times to completely understand it. I'm a bit new to elecronics!

[@paulpkae]

@@Ancipital_ thanks. And yes, watch a couple of times or more and it will sink in.

[@arcticpilotshow4440]

Just discovered your channel and this is high quality educational videos, thank you.

[@paulpkae]

Thankyou. Glad you like them!

[@dacodemonk]

After all these years... I finally understand these things! Thanks a ton! You just got a sub from me!

[@paulpkae]

Great, welcome onboard!

[@DrRChandra]

Very detailed electrical engineering, thanks for all the explanations.

[@paulpkae]

Glad you liked it

[@user-fed-yum]

I remember using the 555 on a game that I made, forty years ago, to win my school science competition. Amazing how long they (and me) have been around.

[@cbm_doomworld]

thanks for a really interesting video. I look forward to seeing more on the 555 and other components. I amcurrently building my own little electronics workspace where I can build stuff like this.

[@paulpkae]

Thanks, glad you enjoyed and please your starting your own little electronics workshop.

[@HeadCodeMonkey82]

Great explanation, you made it really clear and easy to understand

[@paulpkae]

Thanks. Glad you enjoyed.

[@MellexLabs]

This was a fantastic video... the presentation is... chefs kiss 👌

[@paulpkae]

Thanks, glad you liked it.

[@DrexProjects]

OMG. I turned up the volume so I could hear you and after your intro The music almost blasted my face off...

[@paulpkae]

Thanks for the comment. A few people have mentioned this and i have now reduced the level in my intro theme for future videos.

[@danlhoy]

Great video explanation! Subbed and liked! You might want to mention that you need a common ground from the voltage source to your circuit ground in case anyone does this experiment.

[@paulpkae]

Thanks for the comment and especially for Subscribing, much appreciated.

[@shokdj1]

Well explained. I can see why these things were so handy

[@paulpkae]

Thanks for your comment.

[@leonardorissato]

Really well explained!! I hope you get many more subscribers

[@paulpkae]

Thanks. and yes me too, although the count is gradually creeping up. The %views vs Subscribe is VERY low, but I believe that's quite normal.

[@MrCapacitator]

Best 555 explanation I've seen 👍

[@paulpkae]

Wow, thanks! Make sure you Subscribe, there will be more coming.

[@msmeyersmd8]

For me, I get nostalgia remembering the late 1970s starting in college studying engineering physics that included using an analog computer (shoved in a corner storeroom) and some basic biomedical electric engineering design. Isolating the patient from any mains exposure. In the late 1990s, much to my wife's disbelief, I would study/stare at high fidelity analog amplifier circuit diagrams. From vintage tube amps to state-of-art solid state stereo amps. Following the various feedback circuits used to eliminate harmonic distortions. Why? I'm not sure. I had extra time on my hands and it was so relaxing. Just like watching this video. "555 timer" circuits used to be in the many electrical/electronic hobby magazines years ago. Magazines. Gone the way of phonographs, magnetic tape, CDs, laser discs, DVDs, etc. My 2003 Toyota had an electric motor extension for the radio antenna that was broken off in the car wash. It ran every time I turned the car on or off. I thought I could just pull the fuse. It was fused, all right. But on the same circuit as 10 other totally unrelated and multiple necessary things. Probably through some special IC or microprocessor? I couldn't find a "wiring diagram" on the internet and the dealer will not give me a copy. Actually, the dealer has no circuit diagram in the classic meaning of the words. Just broken up functional portions on their computers. I finally had to pull the power wire by accessing it through the wheel well above the tire. I miss the 20th Century. Keep the videos coming. I'm sure I'll enjoy them.

[@paulpkae]

Thanks. Much of the old fashioned approach of trying to fix stuff yourself has sadly gone. But there is a new era of developers, building entirely new and exciting electronics devices out there. I'm convinced the emergence of low cost micro-controllers has fuelled a mass increase in young interest.

[@tincanpete]

Excellent explanation and diagrams, thank you!

[@paulpkae]

Thanks.

[@josephthibeault4843]

I love the 555 many applections think out side the box!

[@chaosopher23]

I just happened to be playing with one, so... TLC55x warning... it will only source 10 mA and sink 100 mA. The NE555's will handle the current. Therefore, I am very happy I spent the money on a roll of 50 MPSA18 transistors! They also have no trouble powering the current-guzzling 555.

[@user-pr2vo2jg8b]

very well explained, thank you

[@paulpkae]

Glad it was helpful!

[@planktonfun1]

I never had the tools to see this, pretty nice to know!

[@ethanjohnston8644]

this is super informative. people are lucky to get this depth of understanding since school will likely not teach this. Could you do a video like this but covering LDOs?

[@gedtoon6451]

What is an LDO?

[@heisen6376]

Liked and Recommended, I'll do whatever I can to see this channel grow. ✌

[@paulpkae]

Thanks very much.