Let's make a function generator (3)
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- เผยแพร่เมื่อ 3 ต.ค. 2024
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Let's make a function generator (3)
This is the final part of our do it yourself functio generator project. By adding a second integrator we change the triangle wave to a sine wave.
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Me: Paul, 49 from USA
Education: United States Navy, University of California at San Diego B.S. E.E., University of Pittsburgh M.S. E.E.
Experience: United States Navy STS, Bayer Intnl Process Engineer
Current: Teaching college freshmen electrical engineering at a small community college in the Pittsburgh Area.
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That series was nice. Thanks for that
Biggest issue I have found when using LP filters, or even an OP amp integrator to generate triangle waves is the fact that the integrator / filters are frequency-dependent. Change the frequency and you alter amplitude, and even lose the wave-shape as you move further away from the 'tuned' frequency of the filters.
Cool, I am gonna have to experiment with the integrator.
fantastic series! I could buy a function generator, but I would not have the background understanding unless I built it myself. It would just be a "black box". Your explanation is fantastic! Now I know what every resistor and capacitor does and why.
I follow your channel and have viewed most of them. I'm a novice Electronics hobbyist (IoT and Arduino projects) and looking for a used oscilloscope. digital are too expensive. there is a local electronic testing lab that's liquidating their inventory at a huge discount. Listed is a Tektronix 2465 for $75. They said it was used by them but don't know the condition. The price is negotiable. would you recommend it? what diagnostic do you recommend? it has a limited self-test. ...or should I save my money for a DSO? your opinion is highly respected! Thanks and great teaching videos!
Correct me if I am wrong, but the IC in the assembled function generator is not a DDS. It is the XR-2206 monolithic function generator and is 100% analog. Also check out the infamous CEM3340, coveted in the synthesizer community. Having said that ... I still cannot get my RC network to transform the 555 square wave into triangle wave ... working on it! 😂
Now this is the circuit i want
Very educational!
Would it be worth your time to replace the other 2 caps with variables for more adjustment? Thanks for "The rest of the story"!
No, the other caps are only for decoupling. .01uF if about right.
Okay, thanks.
I love your videos man
That's awesome, you should make a pcb of this circuit
Hello
Thanks for this circuit
Pls I'll like to know if I can get around 10hz to 100hz with this circuit
Thanks for your demos, I am learning lots. One suggestion: put your oscilloscope more flat on the table and use an overhead cam which has both your board and the scope in the same frame. Much easier than panning the camera back and forth.
I can see how we call the first low-pass filter an "integrator" as the square wave is the first derivative of the triangle wave. But the second low-pass filter is not really an "integrator" as a the first derivative of sine is cosine (i.e., just a phase shifted sine wave). And I think it was you who showed us the 3-stage low-pass filter which generates an even nicer sine wave will less loss in amplitude.
Another useful wave-form for a function generator would be the sawtooth wave, e.g., to drive a raster electron beam. How would we make that with a square wave? Let me guess: playing on the theme of the "integrator", the first derivative of the sawtooth wave would also be a square wave, but with a different duty cycle. 99% low level +, and then a 1% high level -. So I would have to do this square wave with 99% duty cycle and then shift this down, by a lot. Then I guess I need to use at least one transistor to amplify the signal. Transistor or OP-amp? I guess one can do a lot with an OP-amp, but I learn best with more simplicity, i.e., would do just one transistor. ...
all we need is a noise channel and we have ourselves the basis for the same audio signals for the gameboy. cool.
Actually the last wave is a parabolic wave... not a sine wave....it looks like a sine but it is not actually a sine...since integration of triangular wave function gives us a parabolic function...the two halves of the parabola makes it appear like sine
Ok thanks
Thumbs up done sir why did you not put the parts number new subsciber from the philippines
Again great learning video, can the noise be lowed by using a capacitor across the Vcc and ground rails, wonderful video, I will continue to look for your other videos as well, thank you kindly....
will this this function generator work on specifically a CRT TV that has been converted into an osciliscope?
Great project. A quick function generator, always a fun learning experience.
Sir, how we can give offset to our wave in this function generator? Furthermore, Can you please specify values of variable potentiometer and variable tuning capacitor?
Great wee circuit to play around with. Your old haunt in the Firth of Clyde is full of NATO warships right now! Must be an exercise on. Bet it takes you back. Apologies for wandering off topic!
None needed. Yep, I'm sure there are some war games going there. That sure brings back memories. Thanks Davy.
what could you do to clean the sine from dirtyness?
where can i study the math for that circuit1? i looking to understna which variable capcito range should it be as well as the potentiometer range for an interval of 0hz to 3khz
is it the 4 x "tau" formula?
Great wee circuit to play around with. Your old haunt in the Firth of Clyde is full of NATO warships right now! Must be an exercise on. Bet it takes you back. Apologies for wandering off topic!
NATO? Does that still exist? Seems like everything is falling apart back over there these days.
So was brauche ich für Rechteck Spannung
This has been a great little project for my level (noobish) and goes along with the recent purchase of a cheap DANIU ADS5012H handheld scope. What is the range of the adjustable capacitor? I used a 150pF & 60pF which is all I could get and it didn't produce anything so I just used a single ceramic. Anyway I got the square and triangle waves going albeit not as clean as yours Paul but will add todays session to the board and perhaps the two new caps may smooth things out! Im picking up lots of good info here thanks Paul
Really useful thanks. How does the lpf change the wave shape would be interesting. Ta jim
I habe Sinusoide.
Thanks very much for sharing, I will starting tomorrow immediately to build and test.
Thanks
I am a beginner to electronics and I love your videos but I am not a beginner in maths. I rather think your presentation in part 2 and 3 as the circuits being integrators is confusing because the integral of a square wave and a saw tooth wave are not a saw tooth and a sin wave ( see previous comment)
Perhaps a better way to describe what is happening is that the square wave is made up of a sin wave at the same frequency as the square wave and the odd harmonics with various amplitudes. The first low pass filter reduces the harmonics significantly giving something like a saw tooth wave and the second low pass filter removes more giving something starting to look like a sin wave.
You could get a much better saw tooth by passing the 555 output through a transistor acting as a current source to charge a capacitor. ( See I have been looking at your videos!)
Hi,
Please,if you make the drowning with the components and their value
Thanks
Straight forward basic fundamentals are always cool!
Great Tutorial. Thumbs up! Can you then also control the frequency of the sine wave output with the variable capacitor of the square wave circuit?
Would one of those "toy" handheld oscilloscopes be good enough to observe the outputs of this circuit? DSO150 or DS212 for example?
Yes they would
5:18, the cap in series to the resistor. Isn't it coupling cap?
wow, amazing, I am under curfew here in Chile , and that is giving the chance of saving 400 bucks with this 555 function generator, it does work, I did it with few R and Cs, thanks !!!! from Huasco, Atacama, Chile
Awesome!
Good Day. Bro, thank you for sharing. I'm a newbie. I don't see your Patreon link. I see your Amazon link , okay. Hey, what is your set up? How do you handle fumes as you work? Do you use a piece of dryer vent tubing and send the fumes outside? Thank you for your service.
Hello. Patreon is www.patreon.com/learnelectronics. I use the Zeny 875d (I think, I'm not home) no vent. Usually have a fan on nearby.
Im a newbie too and what I did for solder fumes was to buy, from Aliexpress, one of those extractor fans and concertina tubing they use with tumble driers. I taped an old vacuum cleaner noozle to it which I stick as close to the soldering work as I can. The suction is not strong but works if close enough. The other end and where the fan is inserted I put to an open window. To help 'waft' the fumes towards the noozle I also have a small desk fan blowing in that direction. Its cheap and cheefull but works and OK for now
Is the noise, you showed, in the circuit environmental or from within the circuit?
Probably both, but mostly environmental, SMPS powering the circuit, lots of wires etc...
👍👍