#104

This circuit tutorial discusses a simple adjustable sawtooth waveform generator that features constant amplitude and independently adjustable rising and falling edges. The circuit uses simple current sources, a neat little diode ring electronic SPDT switch, and a comparator with hysteresis. Each of these circuits is described, and the overall circuit is presented along with waveforms from the various nodes in the circuit. A PDF file of the drawings in this video can be found here:
www.qsl.net/w/w2aew//youtube/A...

[@clarencegreen3071]

I taught basic electronics for 33 years and I tip my hat to you - you are an excellent teacher!

[@w2aew]

Thank you, that means a lot to me.

[@halonothing1]

I got into electronics less than 2 years ago, though I'm in my 30's, but I was thinking how fortunate I am to have such an abundance of wonderful resources like this to make learning it so much easier. Especially given that I can't read anything more than a couple of paragraphs without a great deal of difficulty. And I can't follow written descriptions of how circuits work for the life of me. But it's hard to find a channel that doesn't dumb down or omit content or keep their videos short so people won't be scared away. I honestly don't think I could have learned about EE without people like this guy.

[@denisvallecilloosorno7355]

Vaya Lástima que no viene traducido al español

[@olinfeil2784]

Clarence Green the best results that ive ever had was by following the Gregs Electro Blog (just google it) definately the most incredible info i've followed.

[@zainulabidin1507]

When you break electronic circuits down in different blocks like you did. Then life becomes a lot easier. You are an excellent teacher.

[@ses4068]

One day you will discover that you can apply this to ANY problem you face in life...

[@Daniel456324]

Long time ago I bought some Signetics NE566N function generator, has built in sawtooth and squarewave output with dc offset. This video sheds light on how it operates. thank you

[@mardav1545]

I am retired from carpentry and decided to try and learn about electronics. Out of all the videos I've watched, you explain things in a way that I can understand. Thanks and keep up the good work.

[@yasirfaizahmed2003]

This channel is so underrated, Deserves a 1B subs!!

[@TheLucky066]

So true

[@hadibq]

It's already exceeding that... A viewer interested in electronics of this level is worth 10k its equivalent of a purring cat video viewers 😀

[@sanjayd411]

I have an MSEE degree from a university in the city of Chicago and have been an engineer for the past 30 yrs. I can tell you that none of my professors taught circuit design like you do on this channel. Kudos to you. Please keep up the great work. I’m still learning from your channel. Many thanks to you sir! 👍

[@w2aew]

I think the problem is that many professors have never, or have forgotten how to design and build actual operating circuits on the bench - where the process is often a mix of known building blocks, intuition and rough order-of-magnitude design - rather than the rigid theoretical / mathematical approach.

[@sanjayd411]

@@w2aew I completely agree. I learned more about designing and building circuits in the job while working than what I learned while in school. Btw, I too am a HAM…de KG9FA. Very pleased to meet you. 73!

[@w2aew]

@@sanjayd411 Nice to meet you too - hope to catch you on the air one day!

[@erikisberg3886]

My sincere compliments for Your ability to teach! Was a joy to watch, from an old EE.

[@patprop74]

I feel like I should be paying you for the teaching! you really explain in a way that fun and easy to learn. Thank you

[@adrianwong26]

I also feel the same. Will w2aew have a course one day?

[@jonahansen]

Great exposition using the minimum needed configuration without all the embellishments to improve accuracy and independent variability of frequency and slopes, etc. Fantastic - I always had trouble with diode bridge switching...

[@roladun]

I felt compel to say you simplify things to the point that it makes me feel lazy brain-wise. How I wish that switching circuit 5:24 is a puzzle for us to decode before you explained how actually it operates. I feel like I am cheating getting answers easily. This is one of the rare KZbin channels that even if one knows nothing about electronics you can still watch and enjoy learning something and feel accomplish for the day. Thank you so much for your teaching.

[@chuckjls]

These simple, fundamental analog circuits are all miniaturized and etched into ICs. It's so great that you are explaining these circuits and how they function. I recommended these videos to a lot of my new interns and junior engineers. Application notes from IC vendors and mfg. leave out a lot explanation due to proprietary restrictions. You are doing a great service to future engineers and some of us old timers who need a refresher. Cool test bench. Our lab custodian at work freaks out when we leave a probe out.

[@rish1459]

I am so glad you walked through that in the manner you did. That is exactly how engineers think when designing circuits. Basic fundamentals to Functional blocks (usually add specs) to tools in the toolkit to Proof Of Concept. Then the fun of debugging those parasitic and/or unintentional effects (e.g., the diodes don't all switch at the same time, temperature drifts, etc. etc.) You should do one on using a transistor's PN junction as a fast (low charge) diode.

[@ZeedijkMike]

I have watched this video 4 or 5 times and find it facinating every time. Simplicity and versatility in the same circuit.

[@DigitalbearDan]

At the risk of become yet another echo among the legions, I cannot resist expressing my gratitude for this selfless sharing of your most impressive knowledge. Your mind is not only acutely versed in electronics theory and practice, but possessed of a powerful gift for transmitting that knowledge to others with an equal degree of skill. I learned at great cost, after even greater frustrations, that I am a solidly visual-kinesthetic learner. Such labels proved to be of little value

[@MC-fk4vb]

Best teacher on youtube! I've been enjoying and rewatching a lot of you're videos for a while now. They're great. Thanks for taking the effort of making them!

[@Disillusioned_one]

Enjoyed this video, never thought of using diodes as a switch. And explained brilliantly, thank you.

[@0MoTheG]

PIN Diodes are being used as attenuators, but I had never seen this.

[@tomaszwota1465]

I've watched these videos (this and the previous one) a couple of times now, I'm new to the hobby and it took a while to get it. Thank you, they are so beautifully crafted, best teaching material I've seen in a while. The different versions of the schematic, high-level to component-level, that was great and it opened a door in my mind I never knew were even there! It's starting to look like hardware programming (I'm not new to programming), and I guess that's a good thing, because I'm not afraid of programming and was very much daunted by circuit design! Still am, but your videos are helping so much! Thank you for going so deep into this circuit which is by no doubt pretty much trivial to you. I appreciate every minute of it, always to the point, no unnecessary padding, distilled essence of what needs to be said.

[@larrybud]

Fantastic! Dang I love how you break down circuits.

[@LordPhobos6502]

A long while ago, back when we had to walk 15 miles to goto school (and it was uphill both ways), I was told of a motor control circuit. Instead of just basic PWM, where the mark to space is changed for a constant frequency, it had a constant mark, but variable space, to ensure the motor did not draw too much current while building up speed. This can be used as a constant mark (or constant space) driver! Thankyou for this video, I learned a lot of new things, and I'm going to have fun playing with this in the workshop 😁

[@kevinkrieg99]

Alan, your videos are amazing. Thank you. I built this circuit in a night and even modified it slightly to replace the current source and sink diodes with green LEDs so I could see when it was on. Running off a 9V battery and works like a charm with an opamp I had on hand. I had a lot of fun adjusting it, learning what each component is responsible for, and the limits.

[@w2aew]

Perfect! I am so happy to hear that my video inspired you to build, test, learn!

[@electron_]

You are a database of electronic knowledge on the entire YT. Your amazing project rewind me back in the days when you could see such great ideas only in the HUM RAdio magazines. Respect! Thanks!

[@educationdz202]

This is actually a really nice way to introduce proper easy and useful circuit design .. many thanks

[@argonman1]

Well, you just got another subscriber. I'm currently trouble shooting a Wavetek 186 phase lock generator from 1980 and you have described their block diagram design almost perfectly. Very helpful, thank you!

[@emcgon]

What an elegant and beautiful circuit. I would never have thought of using the diodes as a switch in that way.

[@MilanKarakas]

Brilliant! Simple and effective. Thank you for sharing your knowledge with us.

[@maxsnts]

This brigs back memories... You remind me of the best analog teacher that i had! Simple and concise circuits that present the fundamentals! Very very cool.

[@ele4853]

Great job! Very well explained together with the hand write notes. Clean, well organized and easy to understand. Thank you!

[@indigoskywalker]

Love watching your tutorials, excellent delivery as always!

[@Hovvman]

This video brings back fond memories of my first circuits lab in college where we breadboarded a simple pong game played on an oscilloscope in XY mode using a similar technique and some analog multiplexers for sequencing between the ball and the paddles. Thanks!

[@landus94]

Amazing job you've done here Sir! I, as a beginner really appreciate these kind of explanations for simple building blocks in electronics. It would be great to see videos like that more often, but I understand it takes time. Thank you again!

[@halonothing1]

I know I've already commented, but I just wanted to say how much I appreciate you taking the time and effort to make these videos. I have a really hard time reading and can't follow written descriptions of how circuits work for the life of me, so channels like yours end up being a huge help. I really don't think I could have learned electronics without people like you putting up these sorts of videos. I spent 20 years trying to find my niche and thanks to people like you, I've been able to find it. Cheers.

[@YTGamme]

Please keep making these kind of tutorials. I love them.

[@erflb]

I've been studying and working with Electronics for almost thirty years and I never thought of something so great and at the same time, simple. Thank you very much!

[@stevegrande1698]

I have been a technician for over 40 years and never worked on a circuit where a bridge is used as a switch. Excellent description of voltage drops and current sources. It is great to see that students today have this medium to use as a reference to understand the work they are doing in the lab.

[@gotbread2]

I never thought about using the diode bridge as a switch. Simple but brilliant! Will use this in the future instead of shuting off the current sources

[@sylvainduteau9780]

Very good tutorial. Simple basic analog circuit yet but used in most electronic integrated circuit. Analog circuit can do any kind of mathematical operations; sum, substraction, log, square root, etc... As we know, digital calculation is much easier to excecute, but analog worl makes it so much insformative as you demonstrated it!! Keep going your nice work Sylvain

[@duperdude25]

You have a gift for teaching. Please keep it up. I'm doing schematics but mostly on digital interfaces, very little analog, and I really enjoy your channel, brings memories back.

[@DigitalbearDan]

in the classroom, however, it DID allow me to seek those learning modes and materials of most benefit. My point being, you not only present what you are discussing visually, via this you-tube channel, but your words (though an obviously auditory element!) paint powerful images, regardless of intention. For this I thank you. I take learning VERY seriously. So your gift is golden to me! -Dan in Chicago

[@emcgon]

I don't know if you are a teacher by profession but if not you missed your calling: you really have a gift for explaining things in a clear and interesting way. I love the format your videos: a little bit of theory followed by a practical demonstration. Thanks (again) for taking the time to make these videos - I am always looking forward to the next one and I always learn something or take away a new idea from them.

[@arenotdiy7280]

You are awesome for putting this out! Beautifully explained and simple, gives me great ideas for my DIY synthesizer. Gracias!

[@Edgarbopp]

This was fascinating and well explained. Thanks!!

[@carlranson9160]

Fantastically clear description. thank you. I never quite got the hysteresis thing until you mentioned that the feedback resistor is effectively in parallel with one of the other two. The light bulb is now on!

[@w2aew]

Carl Ranson I love those ah-ha! moments when the light bulb goes on! Thanks for sharing!

[@PORRFNK]

***** Thank you so much for this, I have been looking to find good explanations for how to diy something like this for fun. Do you have other oscillator designs? How do I add linear voltage control to the frequency?

[@w2aew]

A. Bob You can design a simple circuit that varies the current source values as a function of voltage. Maybe my video on current sources will help. I have some other videos on oscillators, here's a simple search URL: kzbin.infosearch?query=oscillator

[@PORRFNK]

Hi, I was thinking of other designs like quadrature oscillators etc.? Thanks, I will take a look at the other video :)

[@ruijacinto8225]

You made me nostalgic I was a young engineer at fifths decade when the electronic was so beautiful and we assisted the first steps of solid state; congratulations you are a very good communicator I enjoyed to review matter almost lost by the gadgets era

[@darlingtonpear940]

Great take on a relaxation oscillator (sans 555) and a very clean triangle! You've got me thinking about how to vary the frequency and amplitude now, too. Excellent explanation, Thanks!

[@ernestb.2377]

Really nice these small but interesting and educational circuits, and you do a tremendous great job of explaining the working principles. Keep it coming 🙂 and we will build and play..

[@charliesumrell7590]

Excellent explanation of three basic useful circuits.

[@kcbanner]

Thanks for the explanation of the schmitt trigger behavior - it hadn't clicked with me that those resistors become effectively parallel with ground/vcc, cheers!

[@tamarkan]

Classically beautiful...as always...well done!

[@vertamps]

I love everything about this circuit, multiple basic building blocks with good working theory throughout there use. After recent peering of IC designs i have decided people who design analog IC's are some of the smartest people in the world, microprocessor designers a distant second.

[@w2aew]

Thanks - glad you liked it!

[@vertamps]

***** I threw together an LTspice simulation of your circuit. Here is the download link if anyone finds it useful to play with. www.filedropper.com/sawtoothgen

[@valakatz3967]

Thanks again! Great video tutorial, I love the effort you put in your videos. Keep the great work you do.

[@davidsourdis981]

So much electronics knowledge compressed in a short time and transmitted with such a crystal clear explanation. Thank you Alan, 73 de HK1A/K1KK

[@TerminalJack505]

Brilliant. I forgot about the diodes-as-a-switch trick. It was something I learned from a lecture but never used or saw demonstrated.

[@ke9tv]

Nice explanation. I might have added a speedup capacitor on the comparator, particularly if I'm going to use the square wave output (this is a nice variable-duty square wave circuit as well as a triangle generator). 47 pF in parallel with that 3.9k feedback resistor should tame any glitches at the transitions.

[@forbearcali]

Phenomenal tutorial! Inspiring and informative. I hope youtube pays you one day

[@christopherwood8778]

Awesome explanation. Thanks for making this video. Subbed immediately after watching.

[@lategahndotcom]

Alan, I LOVE this. Masterfully explained. Awesome!

[@einball]

Your videos are so simple yet so awesome! Keep up the awesome work! :)

[@octavmandru9219]

Thank you again for this nice circuit. I build it last night straight on a perforated board and it works perfect. I used sockets for capacitor so i can have some flexibility in the range and an SMD rectifier bridge. Sometimes I feel the confirmation of the breadboard is needed, but thanks to your clear explanation I didn't have to. Great addition for my beginner's lab! (Well, I have a Chinese scope with built in DDS but this is small and battery operated)

[@ronaldlijs]

VERY enjoyable and instructive, great work Alan as always.... please keep them up!!!

[@duality4y]

i love this its so clear what is going on, i might even reuse these building blocks if i ever wanted to make something else myself!

[@yeetshea]

Thank you so much! I have been wondering how to create a variable frequency sawtooth generator for audio applications for a while now. Thanks for being awesome!

[@Noscrubjections]

very nice video i appreciate this gift you have given all of us here. kudos!

[@docfoot316]

Enjoyed and learnt all in one ,of to make up this circuit .Many thanks for sharing ur knowledge.

[@acluster3411]

You are a great teacher, very well done.

[@fer_fdi]

Very cool circuit beautifully explained, thank you!

[@MsMammeta]

I've never saw a more interesting channel on youtube. :)

[@makaveli200369]

Great video, diagrams and narration. A++

[@eight-double-three]

Cool tutorial, very useful. I had been looking for this piece of knowledge for a long time now...

[@cbuser1000]

Superb video , I've watched most of your videos and all are Top notch , Both in quality and understanding 👌👌👌 ... Thankyou .

[@equalcrimeequaltime]

Your videos are great! I was getting a headache trying to figure out how to calculate the the linear charge of capacitor which I've figured out is t =VC/I, where frequency is the reciprocal of t (1/t), because I wanted to get the frequency of a PWM thing I'm doing. BTW, most of what I've learned about current sources and generating waveforms was from these videos. You're a great teacher!

[@WPF465B]

Another excellent instructional video, thanks!

[@cugoman]

I watch your videos when ever I feel like I need to learn something new ..

[@321reh]

Your Bench Rocks!!! I'm a BIG FAN of Tek Scopes...Thanks Once Again!!!

[@bhavani1089shankar]

i found the same circuit (not as detailed as this) but in an abstract form i.e with two constant current sources (one is sink) and with hysteresis in Design with operational amplifiers and analog integrated circuits by Sergio Franco and thank you W2AEW for making me understand Franco better

[@w2aew]

Yes, this is (was) a very common basis for analog function generators years ago. It makes a very good example for the application of current sources, diode switching, and schmitt trigger (comparator with hysteresis).

[@MeeBilt]

Fantastic tutorial - so well presented and demonstrated. Subbed 👍

[@T-Tronix]

kudos for another insightful and amazing video. it be nice to expand this in to a handy function generator. your efforts are greatly appreciated.

[@444guns]

Awesome, thank you very much for this. I was actually searching for such a tutorial, while building myself a signal generator :)

[@espennyhaug2716]

Very good video. Keep up the good work.

[@hardrocklobsterroll395]

fantastic video. really quite informative and easy to follow. thank you

[@elviskimani6458]

Awesome explanation, thanks.

[@KetilDuna]

Gorgeous video! Thank you for this.

[@octavmandru9219]

Thank you for another great tutorial.

[@NNNILabs]

Simple, clean and efficient!

[@Zootalaws]

Really well explained - even for a noob like myself. Thanks very much for taking the time.

[@Jez4prez]

I'm studying electronics myself and your videos are invaluable to me :-) You explain more applicable applications that my teachers never seem to cover. Most of my teachers are so bogged down in maths and the theoretical I often think they do it purposely to confuse us students. I think they've all been stuck in the Academia world for far too long haha.

[@viesturssilins858]

This was most interesting, useful and educational! Thank you very much!

[@surferboy36O]

Great video and excellent explanation!

[@N4ppul4]

Great! If im ever going to make a noise/signal generator this would be awesome addition.

[@billywallace1360]

I've been looking at an NE566 I found in my parts box. After watching this video, the block diagrams of that chip showing current sources, a schmitt trigger and square and triangle outputs suddenly make a lot more sense.

[@danielbecker6695]

Something has to be SERIOUSLY wrong with you to see a tutorial of this high clarity/quality and still give a "thumbs down". Really.

[@a000ab]

Very nice design!

[@oswaldocunha9455]

Quiet clear and neat . Thanks a lot !

[@josephbuganski8066]

Very informative, Thank you. Absolutely enjoy your interests on tutoring Electronics!

[@cescofran6165]

Now I know how to set the value of a hysteresis resistor, thank you.

[@VintageLabSilvioPinheiro]

Master, thanks to give us a one more excellent explanation.

[@MrSadPanda]

Excellent video!

[@nikolaytsantsarov4686]

Great Video as usual. Thank you very much.

[@thisnicklldo]

Great stuff - really clear and very interesting

[@KarlA-vk4kn]

Awesome video, well explained 👏 👍

[@monolito8556]

Man I swear this must be the only vid that explains the basics of capacitor on constant current source , and the whole design for a variable ramp wave generator , really grateful for the sharing, one question, how would you solve the problem without the diode bridge, which I also learned in this vid, thanks again

[@w2aew]

If you didn't want to use a diode bridge, you could add some circuitry to directly turn on/off the current sources.