How to create a tuned oscillator at any frequency
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- เผยแพร่เมื่อ 10 มิ.ย. 2017
- How to create a tuned oscillator at any frequency
If you know the formula 1/2piRC you can create an oscillator at any frequency you desire. In this video we create a Hartley-style oscillator at 1KHz using a 741 op amp, 3 resistors and a single capacitor.
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Thanks again and again. You remind me of my manager. We can tell you're in love with this stuff and you enjoy teaching. Teaching is a gift, and you've got lots of it. Keep up being awesome!
This was exactly the circuit I was looking for to make some antenna experiments. Thank you so much !!!!! Keep the effort on this kind of content on electronics fundamentals.
You cannot make antenna experiments with a few kilohertz circuit. This op-amp has a gain bandwidth product of 1mhz, meaning that the square waves generated cannot exceed the frequency of about 100 khz. Also, at that limiting frequency, the signal will become fully triangular instead of square. Op-amps are generally not suited for RF generation. Try one of many different types of single stage tuned LC oscillators (such as Colpitts) if you want to experiment with antenna matching in transmission.
This video was very helpful! Thank you very much!
Increasing my knowledge on electricity, and so far you’re the most clear and insightful out of all thank you :)
The best verbiage I have ever heard , thank you
Super. Interesting.
THANK YOU!
You are genius man thanks lot
Great video, very informative. Couple questions, in the formula when you use R this refers to Rf correct? Also are the other resistor values imperative or do they just need to be the same value? (If I'm understanding correctly it's just splitting the voltage to that input, right?) Thanks.
Thanks for another excellent tutorial:)
Very easy to understand the best video i find in the net, thanks man for your help !
Thank you 👍
Thank you so much now ı now a oscillator's basics
Wow thanks
i LOVE You as a teacher ! im learning electronics to save my life without taking forever in the process... you are clear, paced, and you give very helpful detail along the way..... i learned here what i wasn't learning elsewhere so, Thank You Very VERY much ! ( and im still alive btw )
VERY NICE
very easy, simple & professional. many thanks goes to you.
I tried your circuit using simulator. Output gave out a square wave instead of sine wave. I googled the circuit and found that it is called relaxation circuit, which is used to generate square wave. How did you get the sine wave from the output without additional components? I am bewildered by your demonstration.
I think you’re right Shue Wing Tam
Gotta use a positive and negative rail supply. He used two 9v batteries hooked together, so 18v.
😂OK it is the fundamental square wave generator.🤣
Nonsense. His frequency formula is incorrect, the output is square, never sinusoid, this op-amp will generate in the order of a 50 khz maximum, to talk about a 10 mhz range is pure nonsense. I appreciate this gentleman's love of experimentation, but he is not in the position to instruct others with this level of knowledge. I am sorry to say.
Got it, swapped some caps in and out and got reasonable sine wave 12KHz, All good wholesome fun, cheers. ps.( reciprocal of 2pirc) works spot on..splitting supply rail very interesting..
Bruh this is cool I did not learn this in circuits basics
Simple and easy to learn 741 is an IC often used in audio circuit and a RC combination has its limits. But we can try other ic's with higher frequency cut-off range.
Hello...why not use a nice multi-turn pot as your feedback resistor for fine (or total) tuning with an appropriate capacitor for the desired range? In cases like this, II usually add a small fixed resistance as to avoid "crashing" the output if the pot is turned to 0 Ohms.
A jumper to connect various caps may be useful...
you are awsome
What can I say !!!,,,,,, you are a master . thanking you .
Is it reasonable to make a osc. in the Mhz (lets say 1 Mhz) and then use a freq. divider to get a stable and precise 100khz oscillation?
Can I change the frequency of an audio mixer Channel EQ band by doing this? For example my audio mixer low band knob is 80hz, I want to change this to 60hz.
Perfect explanation, thank you very much for sharing.
Glad it was helpful!
Can this design use for ac sine wave or i would need to use towo opamp to get the ac signal
Can I use this op amp as carrier frequency e.g for radio transmitter
What effect does b+/b- stability have on the circuit?
What's the advantage of using this setup over a Colpitts oscillator using a tank circuit?
I tried this circuit. I was able to get as high as 215kHz, using 680pf, but anything further would not give me a clean output. I guess that's where the LM741 starts to limit?
Nice one .... thanks
Can we make a transmitter with this..by applying audio signal
Can you use a BA4558 op amp to do this..??
How do i use the op amp on a
split supply if i am using pin 3 for the oscillator timing?
Very simple circuit. Good explanation. Thank you so much for making this video. Components are also very cheap.
like to see ya add a varicap in series with your cap allready in place and tune it electrically. thats kinda where i thought you were going with the title
You might try a TLO82 op amp or similar op amp with a jfet input.
But how does this circuit do to do the oscillation??
Can you generate the Schumann 8.????/ sine wave low output with this lay out?
05:48 So how does it work that it produces such a nice sine wave? The charging/discharging characteristics of a capacitor aren't quite sinusoidal, they're exponential. So where does the sine come from?
This circuit does not generate sine wave, it generates square wave, he uses same circuit in one of his tutorial to use it in function generator, he uses two other stages as op amp integrators to change the form of the wave to triangle and then to sine wave, but how comes in this tutorial it generates sine wave 🤔?
@@manofmesopotamia7602 Oh, so it's not really a sine wave, but its 2nd-order (parabolic) approximation. If you integrate a square wave (which is basically a constant piecewise function), you get a 1st-order (linear) function (which, piecewisely, is a triangle or sawtooth wave). One more integration and you get the 2nd-order function (parabolic). It might look like a sine, but it really isn't, and I'm pretty sure that the difference could be heard by ear, because if you Fourier-decompose a parabola, you get a whole bunch of higher harmonics.
@@manofmesopotamia7602 Maybe he changed the y axes down so it looks like full sine wave not half ?
The output is a square wave with slanted ramps, the signal on the -ve input of op-amp would resemble a sawtooth with exponential features. There is no sinusoidal signal to be found in this circuit, anywhere! The frequency formula is wrong as well. Please do not try to learn from someone who does not know and what is worse, does not realize he does not know. Also, this particular op-amp is capable of generating decent square waveforms up to a couple of kilohertz, no more. To talk about a 10 mhz capability is plain stupid.
How can I increase the current that the oscillator can put out?
Where I have to put the 2 output cables for the hf ac ?🤔
why use a variable capacitor? why not a variable resistor? like to vary the 1k5 resistor instead of the capacitor.
hi do you have vco tut?
hello sir! can I just use a variable resistor than changing capacitor?
If the frequency is 1 / (2 * PI * R * C), what will happen if you change R? Yes, the same like when changing C....
Found my new teacher here.. thank you sir.. 👍
Just subscribed. Your videos are great for someone starting, like me.
Awesome, thank you!
sir as per your circuit diagram it a diagram of astable multivibrator using opamp .
so how you generate sinewave ??
its o/p may be square wave .
Ideal output should look like rising an falling exponent, but Opamp used is slow, so the corners are smoothed out.
so if i wanted to control a servo motor this would be the way to make the control signal to the servo? and to control a step motor?
It would work, but it's not the best way.
Using a trimmer on Rf will fine tune freq, am I right?
According to page 4 here www.diodes.com/assets/Datasheets/LM358.pdf "Pulse Generator" image, it's possible to put a capacitor with polarity. Perhaps an electrolytic capacitor ? So can it work in your circuit ?
It's a pulse generator different from this circuit, en.wikipedia.org/wiki/Relaxation_oscillator#Comparator%E2%80%93based_electronic_relaxation_oscillator suprisingly wikipedia explained it well, look at the "Transient analysis of a comparator-based relaxation oscillator." Image. The capacitor bounces between 0.5v and -0.5v so it's not a good idea to put an electrolytic capacitor in here also it's frequency characteristics are not suitable above 10 khz watch this: th-cam.com/video/WytU5uj78-4/w-d-xo.html
Hi. I made this circuit in circuit wizard but I didn't get any output. Do you know why this could be.
I need to tune my oscillator to around 500Thz to drive a solenoid through a relay and create light. How would i tune my oscillator to that frequency?
👍❤️
what influences the size of the waves
is this at all possible with electron tubes
Hey Paul. How long does it take you to get a vid like this ready ?.seems like your doin a lot of testing and math to get to the final take lol. Just so your viewers know the work you do to get the quality of vids your sharin. Ty.
About 8 hours to make a video
@@learnelectronics ty man. We do appreciate it
I have a behlman oscillator can I tune in to a frequency of my chosing???
i finally got around to building that circuit, it doesnt work :C. i replaced the 1k resistors with 10k, cause i had them lying around. i figured that wouldnt make a difference. and i replaced the 1k5 resistor with my 10 turn pot (100-10kOhm). it just stays at like 3 volts or so. what voltage did you supply to the circuit? i tried with 5. any clue why it doesnt oscillate? ill upload a video of it tomorrow on my electronics channel
/edit: i tied v- to gnd and v+ to 5v, could that be an issue?
Yes it could. With a 741 it needs to see a positive and a negative supply. I use a 18V supply consisting of 2 9V batteries so the op amp gets +9V and -9V with gnd being the common between the batteries.
yup double supply did the trick. its just hard running that of a single lipo cell :P
Did you use both a positive and negative voltage rail. (+5,-5)?
what is max frequency we are able to make with this? for bigger like 50mhz need other op-amps? this question should be several guys request thanks
You will be lucky to get 1 MHz with the 741 op amp. You need to use a transistor to get the higher frequencies. A Colpitts oscillator would work well for 20 - 50 MHz.
@@benthere8051 AS video says 10pf not give 10mhz?
@@seyedmarashi - I doubt you could get it to work at 1 MHz, much less 10 MHz. The maximum slew rate for a 741 is 1.5 volts per uS. The entire period for a 10 MHz wave is 100 nS. There are MUCH better op amps to use at that frequency. The minimum bandwidth for a 741 is 400 KHz. You might be able to hand-pick some that would work at 1.5 MHz.
@@benthere8051 Thanks a lot, last question! any part number that you sure replace with 741 to make bigger frequencies?
@@seyedmarashi You can make HF oscillators using standard 74HC14 that will work at 20 MHz or better. Go to TH-cam and search for "Crystal oscillator using Hex Inverter".
Now I need to work out how I use this in ham radio construction.
Same here! hehehe :D
This really is not stable enough for that application. You need either as xtal controlled oscillator and/or a PLL. You could use it for CW or may be AM, not stable enough for SSB phone.
@@scotttheis9345 thanks! 👍🏻
@@scotttheis9345 Thanks for the advice Scott.
BTW, it is a good video. I shared it on my ham club's website.
Thanks for a great video and explaination but could you tell me what is the maximum frequency that such a oscillattor can be tuned to
Thanks, very nice and easy to understand video. Deducing from your other (NE555 based) oscillator circuit - if I differentiate the SIN output once I can get a triangle wave and differentiating it twice I would land up with a square wave. Correct? or is it too simple thinking?
They won't be perfect, but yes you are correct
Differentiating (or integrating) a sin wave produces a sine wave. Sinusoidal in nature, there is a phase shift.
I believe you may be able to get rid of the clipping using the offset null inputs on the 741.
1. what is 1k5 -> 1.5k ?
2. would it work at 850kHz?
Hi there, I might build this one, is 18v essential ? Would 12v do the job..?
Hi David, 12V will work just fine. Keep in mind that you need a split supply. The easy way is to use two nine volt batteries. Connect the neg from the first battery to the pos of the second. The pos from first battery is your +9V, the neg from the second battery is your -9V and where you connected the two wires together is your ground.
OK, thanks Peter, I'll wire it thus and let you know how it goes. I really like your videos, you and Big Clive are my favourites (it's the style, manner, voice and content)..
You also can use a 7660 to create V- and V+ voltage, very easy to make.
Can it be used for FM radio with a tuning capacitor from 1pf to 50pf?
travis moore
Not possible, cuz the maximum frequency response of 555 is 500khz and articles say 2Mhz
@@Mulazim. What about the LT1677 op amp, Besides you don't need gain for the oscillator just the audio.
and the o/p frequency is 4.5 khz
Is this how processors get there Mz and Gz speeds? Through oscillators?
Strange, when I simulate 100nF i get square output. Is it possible to make sine output?
Gotta use a positive and negative rail......he used two 9v batteries hooked together, so 18v
what would I use to get 60hz?
Can this be made as a variable sine wave oscillator?
Yes and in order to do that you need a pot(potentiometer) and put it in place of the 1k5 resistor
@@Deutz-fahr-101 thought that might be the way. Thanks.
Peace.
With the amount of information you provided, this video should have been no longer than 2 minutes.
Don't like, don't watch. Buh-bye.
This is an excellent video!!! I had one question though, what kind of source are you using to drive this circuit?? Ac? or Dc? and what voltage?
DC I believe
@@youssefdirani thanks
@@stephendavis1837 wlc. I will be trying this circuit right away now. I'll tell you the results
@@youssefdirani Awesome! Thanks, I look forward to it
Can u make that to 50-60hz sine wave?
tene sri pranav ... I would love to know this too ? 🤨🤨🤨🤨🤝
it will oscillate as a semi triangle wave or square wave depending on where you choose to be output
See: noisehackerspace.com/build-lfo-eurorack-relaxation-oscillator/#more-1801
Am new to this so if i wanted to get 2 high and 2 low i would need to parallel two chip
Another great video Paul. I realise this is a fixed circuit design. How cool would it be to use a trimmer cap, or small air variable cap.? I think it would be cool to see the frequency oscillation change on the O-Scope. Yeah I said it(O-Scope)lol
It says Any frequency. But the 741 can't oscillate above audio frequencies. 100 kHz is probably not stable, and I bet your chances of getting to oscillate at 1 MHz are the same as winning the lottery. So it should say any audio frequency. Thanks for the informative video.
Well I tried it with the only op amp i had, which happens to be th TL082. It can oscillate at 1 mhz and some khz beyond. It is low noise and high frequency so if you need that frequency try with the 082 or similar. It could work with rail to rail op amps too
Hello, excellent explanation, my question is, how to send that frequency at about 3 meters through an antenna? Thank you
Can this oscillate at 50/60Hz
How stable is it
Hey there Peter, got it going ok, but wave form looks like an acme thread profile and frequency 2.1 KHz. I'm using a TI chip and a ceramic cap. i'll do some htt (highly technical tinkering) and report back in a day or two, again many thanks.
I respect a man who knows what an acme thread is! (hobby machinist here)
Yes I got the same profile and not the ideal sine wave that was shown
Please help? I can't get this working right. Here is a link to the pictures of my build and the (incorrect) oscilloscope output: imgur.com/gallery/tTP987v
I just can't seem to shake out why I'm not getting the oscilloscope readouts that he gets in the video. Would really appreciate any help!
P.S. I did hook up the dual 9-volt power set-up just as he described in his video's comments.
Could we use this oscill for power inverter?? 🤔
No, signal only
@@learnelectronics can't we amplify the signal ?
Was anyone able to get MHz frequencies with this? Cuz mine works fine at the khz level but not at MHz level
how this circuit work?
what's this "1k5" notation? does that mean "1.5k"?
Yes
can this be made adjustable with a pot?
fredlllll somewhat. the capacitor adjusts the range, and Rf adjusts the frequency.
could be useful if i cant get my 555 circuit to behave like i want it to :P all i need to adjust is frequency from 38kHz to 48kHz
fredlllll this would work well for that.
Why is the waveform of the output sinusoidal !? 😮
What if I want frequency of 1800 - 3000 Mhz
Here is an idea, make a frequence dependant switch, that turns on an led at a giving frequency
but this circuit makes a square wave not senoidal
Can i use polarized capacitor in this circuit?
OK, this is the square wave generator only. I don't know, where he found sine wave!😂And how many grateful ones?
How do you create a circuit with a frequency of 500 mega hertz
God I'm getting so sick of constant conflicting information.... ur video says if u go down to picoFarads u will be in the Megahertz range... is that just theoretical cuz I've read CONSTANTLY that using an op amp for even 150 KILO Hertz will not work or at least not work well... I forget if it was slew rate or just that it would be unstable... plz someone help me
The example must be on transistor
what is 1k5?
Heloisa: Ya, what is it? If he means 1.5 k, why didnt he just say so??