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More circuit fun! Here is a flexible ramp generator circuit that uses a 555 timer and a couple of op amps. The ramp speed, magnitude and offset can all be freely adjusted. It was designed to be used with a function or signal generator that has a voltage controlled frequency input. By doing this, you can create a signal that sweeps linearly between one frequency and another. This is a very useful thing when testing many circuits including receivers, filters, amplifiers, etc. For those interested: the non-linearity at the start of the ramp is due to the dielectric absorption (soakage) that is prevalent in typical electrolytic capacitors (charge stored in the dielectric material). The effect is less pronounced in tantalum caps, and much better in ceramic and film caps. This is one reason why electrolytic caps are not recommended for critical or precise timing applications. A copy of the drawings from the video can be found here:
www.qsl.net/w/w...

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15 окт 2024

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Комментарии : 171

@mglepd 3 года назад

Alan: I recently found your RU-vid channel. It's a great resource for someone like me who is learning electronics. Thanks for going to so much trouble. Appreciate it!

@oliver1224 Год назад

A great video. I really liked how you explained it. I'm hoping to have a go of your Ramp Generator circuit. Thank you.

@howardhall2300 5 лет назад

Thanks for the great advice; once I had the LM331 connected to the variable voltage supply I could see clearly that the frequency was in the hundreds of KHz's instead of the tens of KHz's. The timing capacitor on the LM331 was not connected properly. Now with the 220uf cap on the 555 timer of the ramp circuit I can see the straight line of the ramp circuit cycling up from zero to about 6volts on channel one and the LM331 square wave sweeping on channel two; beautiful! Now I just got to try and remember where I put those IF cans I salvaged years ago! Many thanks.

@w2aew 5 лет назад

Nice! Sounds like you're making real progress now!

@W1RMD Год назад

Thanks for sharing this great and simple circuit. 73's!

@haroldkinley1263 9 лет назад

I built this circuit and it works great with my function generator sweeping it through the VCF input. The offset control is very useful. I also use a X10/X1 resistive divider so that I can have better control of the offset voltage feeding the VCF input. A 10-turn pot for the 5k offset control might help to set the voltage more precisely. Works great! Thanks for the video and schematic.

@w2aew 9 лет назад

Awesome, this is the exact application that the circuit was designed for - I'm glad to hear it's working so well for you.

@DAVET38 11 лет назад

Another good video Alan. I really enjoy the circuit analysis as well as the circuits you present . Thanks

@ohmedarick1 7 лет назад

Now a know what the VFC/Mod input of my frequency generator is for. Thanks as always!!!! Great Video...

@Skipperj 11 лет назад

Very good stuff Alan.You just gave me an idea for a motor control circuit.Thanks so much.

@039dalekmoore2007 6 лет назад

I have constructed the circuit and it works as shown i am using a BC559 for the transistors and a Tl072 for the opamp's ..my circuits i constructed 2 for my low line rate multisystem television 32 line 60 line 128 line ,i can do higher line rates but am testing with these for a start .

@spiderspider1384 Год назад

Hey dude, great explanation about the ramping process. I had a doubt about making a ramping circuit for high power over 1 kW , with adjustable ,frequency, ramping duty cycle and amplitude Could you recommend a circuit .

@TutorialsGuru 3 года назад

The Number 1 Step of Making an Electronics #Jammer Circuit that nobody talks about. Just put a Zener Noise generator for white noise and the ramp in the carrier to sweep.. now mix it... Am I right? @w2aew ??

@maximiliansiath7604 4 года назад

Just a quick couple of questions. You mentioned in the end that this circuit could be improved upon with the implementation of other devices. Out of curiosity what type of devices would those be? And by doing so what specs of the ramp generator would they improve?

@w2aew 4 года назад

A better rail-rail op amp will give you a larger ramp voltage swing. Timing capacitors that have less soakage will give a more linear ramp (electrolytics are bad this way). A different design for the main period generator will give a wider sweep frequency range.

@RepairRadioLab 19 дней назад

this one video answered all of my questions ..

@ahnuts72 11 лет назад

Thanks Alan. I was looking for something to sweep the vcf in my fg-502 to test some filters I was building.

@tonyl8242 4 года назад

Thank you! Really enjoy watching your video. You made everything easy and clear. Great job!

@overengineeredinoz7683 Год назад

Well explained as usual. Thanks.

@hardwareful 11 лет назад

Thanks for the video! I love the circuit, made me want to build an automatically scanning dipmeter using a CD4046 VCO, opamp threshold detector an LF298 sample&hold circuit. Would love to see that as an addition to this video, too ;-)

@rusga3574 Год назад

I made your circuit. I want to use it with the JDS8080 generator in VCO mode. I connected a DC power supply to the generator. By adjusting voltage of 0-5 volts pp , frequency varying in range. When connecting the sawtooth signal (0-5 volts pp) , there is no change in frequency in range - no sweep . What am I doing wrong? Thank you.

@dm.2023 11 месяцев назад

Can you modify it to sweep or ramp up the amplitude of an incoming signal rather than the frequency

@howardhall2300 5 лет назад

I'm taking the output from your circuit and passing it to the input of a LM331 voltage to frequency converter; my multimeter says I have about a max of 3.6 volts on the input and about +or- a few mv's on the out put of the LM331. I can see the start and stop of the signal matching the ramp voltage on the oscilloscope but not much else. Do you think this is just a lack of power to the LM331(which in the datasheet says it needs 10 volt on the input for "full-scale" or am I on the wrong track? Again many thanks for the circuit.

@w2aew 5 лет назад

This should work well with the LM331 to create a sweep. So, without seeing a schematic of what you're doing, it is difficult to say what is wrong.

@Valenorious 11 лет назад

That rounded starting edge of the ramp, what's the cause? Is the transistor charging the capacitor doing non-linear business? Or are the opamp stages getting within Vcc or Gnd margins. (shouldn't be so, as it has a symmetric supply of +9 and -9 volt). Or something else?

@holden0 2 года назад

Any idea why the dip or negative spike in the beginning of the sweep appears? Also, I see somewhat of a curvature before the linear part. Could it have something to do with the current source lagging and not being able to supply a constant current immediately in the beginning of the ramp? I saw that same phenomenon in other types of ramp gen circuits I tried, even with op-amp based gens.

@w2aew 2 года назад

This has to do with a property called "soakage", or dielectric absorption, that is prevalent in electrolytic capacitors. When a charged electrolytic capacitor is quickly discharged and then left "open", a small residual charge returns to the plates. What you are seeing is this residual charge added to the charge being delivered by the current source. This results in the quicker, non-linear growth of the voltage on the capacitor at the beginning of the charge cycle. See en.wikipedia.org/wiki/Dielectric_absorption

@Kilohercas 10 лет назад

hey, quick question, maybe you know how to make ramp down waveform with 555 chip that could be triggered for single shot mode ? somehow i can't figure out

@TeorijaSHD 7 лет назад

Thank you, Alan for your videos, it's great pleasure for watching. I have some questions about this circuit. There is a small non-linearity in the ramp begin. I've made part of circuit - 555-timer + transistor current source and it's quite linear in wide period ranges. It might be because of op-amps. What characteristics of opamps are critical to avoid non-linearity? And one more question, disturbing me: why discharge level (minimum voltage of ramp) is dependant of capacitor value ?

@howardhall2300 5 лет назад

Thanks for replying, I've just added the basic voltage to frequency circuit as given on the Texas instrument's data sheet for the LM331 to your circuit. I've connect the ground of that circuit to the ground of your circuit. Will I blow the LM331 if I connected the ground of its circuit to -9v of your circuit. I know I should just try it. but my caution is due to the fact that I only have one LM331 at the moment! Again, thanks for all the inspiring content on your channel.

@w2aew 5 лет назад

Connecting the grounds of the two circuits was the right thing to do. Best thing to do to debug it, is to separate the two circuits. Setup the LM331 circuit alone, and drive the control voltage input with an adjustable DC voltage to be sure the Voltage-to-Frequency converter is working as expected. Once you have this working, then make sure that the ramp generator is working, and adjust the amplitude and offset of the ramp as needed, and connect it to the LM331 control input.

@ChrisWilson5006 11 лет назад

Another excellent video and explanation. Alan, have you ever considered doing a PCB design for some of them and sharing the file so we could make a small board for them, rather than breadboarding? Thanks!

@FrozenHaxor 11 лет назад

I love your Nixie frequency counter, its lovely in it's simplicity! I got an old Nixie f counter unit myself, but it needs some work yet, very inaccurate... Also I like those pots! Cheers.

@kevintice6851 16 дней назад

Hello. Love the circuit. The schematic in the video is blurry. Can you send me a copy. This circuit will work great as an image ramp for my light show system. Thank you 1:20.

@kevintice6851 15 дней назад

Some sections of the video clear up as you watch it. I was able to copy the schematic. Built the circuit with a dual rail op amp, ran everything on +/-15V, changed a few component values, and the circuit works great. Running 0.6Hz to 8Hz for my application. Thank you.

@suhas210 8 лет назад

Good Circuit, tested and working.

@ewkakau 11 лет назад

Great video, I like your simple explanations thanks. Maybe you could share your ideas on how to make frequency counter with external oscillator (i.e. OCXO or even rubidium), I think it would be interesting video too.

@MYNICEEV 11 лет назад

A very good educational tutorial for this thicko. My expertise in electronics is miniscule and I was able to follow your tutorial very easily and comfortably. I too like those pots. may I make the same request for supplier and part number please. Once again this video as are all your videos is great. Many many thanks.

@RicardoPenders 3 года назад

I have a burning question about this circuit, I made the same circuit on my breadboard and followed your schematic but I didn't have the 5K ohm pots, I only had 10K so that's the only difference, the rest of the circuit I made exactly the same. I'm using a computer power supply so my input voltages to the circuit are GND, +12V and -12V where you used 9V batteries to create the +9V, and -9V, other than that everything is the same but the output I'm getting is a flat DC voltage that I can move up and down using the 3 pots so that's working, however I'm not seeing the ramp being generated, the 555 output oscillates at about 80KHz. What am I doing wrong?

@w2aew 3 года назад

If you probe the collector of the PNP transistor, what do you see there?

@RicardoPenders 3 года назад

@@w2aew Well, I do see a pulse on the collector and I can change the pulse a little bit with the variable resistor but I'm not getting a signal from the opamp which doesn't make sense. I made a video to show you exactly what I see so I hope that you can make sense of it and maybe explain it to me what I'm doing wrong. Here's the link to my video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4BREBtSiCVg.html By the way, I now got the opamp output working so I can change the DC offset and the other setting too, however because there's something wrong in between the transistor output and the opamp input I don't have the ramp signal being created properly or it doesn't get sent to the opamp input so the second opamp output where you take the output signal for the scope is showing a DC voltage only and no ramp being generated.

@w2aew 3 года назад

@@RicardoPenders I am not sure what is wrong. The voltage at the collector should be a slow ramp. Are you sure that you have the transistor wired correctly (and that it is a PNP). You can disconnect the 100K resistor to the op amp circuit to isolate the 555 circuit by itself. As an experiment, you can try removing the 2N3906 PNP transistor, and connecting the 470 ohm directly to the timing capacitor. This should give you a curved ramp.

@RicardoPenders 3 года назад

@@w2aew of course, why didn't I think of that. I know for sure that the transistor I'm using is a PNP and I know the pinout because I've tested it with my transistor tester, you know those cheap Chinese testers right? So if I understand it correctly, the transistor should have the ramp signal on the collector that also goes to the opamp input via the 100K resistor, right? And the goal for me is to figure out getting the ramp signal showing on the collector of the transistor and when that's working I can connect the 100K ohm resistor again so I use that signal to make the two changes to the signal with the use of the opamp and the potentiometers, which is the DC offset and the gain, right?

@alanwolke6253 3 года назад

@@RicardoPenders Yes, the transistor and the associated resistors forms a constant current source (whose current depends on the potentiometer value. When this constant current is injected into the timing capacitor, it creates a linear voltage ramp. To test things, simply replacing the transistor circuit with a resistor from the positive supply to the timing capacitor should result in similar circuit operation except that the voltage ramp won't be linear (it'll be an exponential curve). This will at least help you to ensure that the 555 is configured and working properly.

@AZMReece 9 лет назад

Is this sort of scan (at a lower frequency) what's used for the trace on analogue oscilloscopes? ...With the voltage changing where the emitter points?

@keithostertag 11 лет назад

Hi Alan- Your sig generator's VCF input is not a common feature, is it? I have several sig generators and none of them have anything I recognize as a similar control input.

@misbahpatel6035 5 лет назад

Hello sir, i have a query regarding how to increase the power of function generator signal upto 60-80Mhz using an Amplifier?

@sayantanmaiti2513 2 года назад

Is it possible to make a reverse sawtooth wave using this ckt???

@AntiProtonBoy 11 лет назад

That poster around the 7:50 mark looks rather interesting. What's it about?

@johntraxis2714 11 лет назад

I have seen sweep generators that have an option for either linear or log sweep. What is difference between the 2 types of sweep? Where would you use one or the other?Can you do a video showing how to align an IF section of an AM radio using a sweep generator and an oscilloscope with a demodulator probe? Can you show the if pattern on the oscilloscope screen with the peak at 455Khz and maybe two marker frequencies on either side if the 455khz peak frequency? Thank You For Reviewing! John

@paulcollins664 7 лет назад

Alan I'm still using this little ramp generator for adjusting I F sections when I need to it works really well with it's success, I've gone on to making a lot more test equipment for the shack, I enjoy building much more than ham operating at the moment. 73 Paul M0BSW

@w2aew 7 лет назад

Glad to hear it Paul! Thanks!

@RicardoPenders 3 года назад

Cool, do you have a video on how to make a VCO with a 555 timer and OpAmps?

@w2aew 3 года назад

The first part of this circuit *is* effectively a voltage-controlled-oscillator. The frequency of the output is a function of the 5k potentiometer labeled "speed".

@stefflus08 8 лет назад

Great stuff, I'm very glad I found your videos! Quick question though, what kind of current will pin 7 be sinking? Or put another way, what is the fall time?

@w2aew 8 лет назад

It depends on the value of the capacitor, and the particular 555 being used. Thus, you really can't predict it very accurately.

@stefflus08 8 лет назад

I was thinking of your schematic with the 22uF (later you up it to 220uF?), and for no particular reason other than being curious :) While I was looking at your schematic I realized this is the first time I've seen (or noticed) such a large cap being discharged (or charged) that fast through the 555. I guess partly I was wondering if I was to build it whether to add a transistor stage for longevitys sake.

@carriersignal 9 лет назад

Another fantastic video! Thank you!

@rubenklobertanz4597 8 лет назад

Good Circuit, tested and working. Adjusted to produce 0/+10 Volt sweep. (12V supply) Thanks. Is there a posibillity to add Log/Exp output voltage? This means 0 to +10 V in an logarithmic/exponential way. Tried to add an lin/log simple voltage converter (the one with an opamp and a transistor in the feedback path) but not working as expected. Any hint? Regards, Ruben

@w2aew 8 лет назад

+Ruben Klobertanz The devil is usually in the details of getting the bias/offset correct.

@lalitgohate14 9 лет назад

can we just generate single ramp up of supply voltage, with high ramp up time e.g. 50v/ms?

@GeorgeGraves 11 лет назад

I love the pots - they look really breadboard friendly. Part number?

@wa4aos 10 лет назад

Always Excellent! Question: what stage would this ramp go into on a function gen if you don't have a VC input?? Thanks... 73 Glenn WA4AOS

@w2aew 10 лет назад

It's not possible to generalize because function generator designs vary greatly. It will entirely depend on the function generator that you have. Depending on its design, it may or may not be possible to hack a voltage-controlled sweep input.

@sherifamr4281 4 года назад

excellent video, can i get a constant 100 khz ramp signal by this circuit ?

@w2aew 4 года назад

No, this circuit will likely not be fast enough for that.

@howardhall2300 7 лет назад

Thanks for the circuit, have built it, everything works except for the fact that the ramp is reversed ( starts High on the left, goes low on the right). Have rebuilt the circuit, but must be making the same silly mistake each time. Any help would be greatly appreciated.

@w2aew 7 лет назад

Are you sure you don't have your scope channel inverted? Many scopes have an "invert" function on CH2. Make sure that's not on. The collector voltage of the PNP should show the correct up-ramp signal. It will be inverted at the output of the first op amp stage, and then inverted again at the final output.

@howardhall2300 7 лет назад

Thanks a lot for replying; that was it! I had eyes but just could'nt see what the scope was telling me. Again many thanks. BTW hope your on the mend.

@patprop74 7 лет назад

that circuit looks like a simple metal detect circuit, I have a timebase bistable and ramp generator socket on the front panel of my oscilloscope how would i go about using ? do i use the ext. trigger mode for it? I read that its running thought a Schmitt trigger, does this mean I can measure LCR with it ? Caps and inductors ?

@w2aew 7 лет назад

I would imagine that the timebase bistable is a squarewave that is tied to the horizontal timebase of the scope, and the ramp output probably corresponds to the sweep. Tough to say without knowing what scope you have though. The bistable might be usable for TDR or cap/inductor testing.

@patprop74 7 лет назад

www.dropbox.com/sh/d5wi2jhh34xahss/AABr7NNH-My5hgLHEcN5JoSua?dl=0 the Manual is in the drop box if you have the time. its mention on page 12, and I also re solder that lost wire which help with frq noise.

@TheSoundtec 11 лет назад

I would like to add a meter that would display only the DC offset. Any ideas? Two meters one showing DC offset without Ramping and another Meter showing Peek DC voltage would be really nice.

@SimpleEnough2k9 11 лет назад

Alan, could you tell me where I can get potentiometers like the ones you have on your breadboard ? I don't know if I'm using the wrong keywords, but I can't seem to be able to find them on eBay for instance. Regards.

@dadwillmake 6 лет назад

How does the circuit have to change when using 5v?

@spexnola5427 7 лет назад

Can this circuit be used within audible frequencies (20 - 20k)? I am looking to design a circuit that generates a variable frequency sawtooth wave oscillator, but would like to sweep within those frequencies of 20 Hz. to 20 kHz.

@w2aew 7 лет назад

This circuit does not create frequency sweeps itself. It only creates the voltage ramp that you then apply to the control/tune voltage input of a sweep oscillator.

@spexnola5427 7 лет назад

Thanks for getting back to me. Just to make sure I understand. This circuit is used to shape the waveform, but in order to get that frequency range of 20 - 20k, I would have to apply this signal to a sweep oscillator circuit?

@w2aew 7 лет назад

Not quite. Many function and signal generators have a VCF input (voltage controlled frequency), where the voltage applied to this input is what sets the generator's output frequency. This circuit is intended to drive the VCF input to cause the generator to perform a frequency sweep.

@ident42 3 года назад

You mention you would have done this from less common components; Might could you elaborate?

@w2aew 3 года назад

There are always different ways to do things. For example: The two op amp stages could likely be combined into one to control ramp rate, offset and gain. The pulses generated by the 555 could be done with a simple op amp relaxation oscillator.

@RobertGallop 11 лет назад

Circuit fun indeed, thanks for another great video!

@gerardcasadeval3311 7 лет назад

Hello, I'm trying with a friend this circuit and we want to make the sweep frequency oscillator but we do not understand what we have to put to the circuit for obtaining the sine wave oscillator output. I apologize because we are not english and it's a little bit difficult for us to understand you. Thanks.

@w2aew 7 лет назад

This circuit does not create the swept sine wave output. It only creates a voltage ramp that is designed to be connected to the VCF (Voltage Controlled Frequency) input jack on a Function Generator, such as in the lower right corner of this picture: d2ydh70d4b5xgv.cloudfront.net/images/3/9/elenco-function-generator-gfg-8016g-6996c99b05da5dd8b9245cef18b1dd90.jpg

@gerardcasadeval3311 7 лет назад

Do you have any idea how we can get a sweep frequency oscillator? Thanks for the fast response

@w2aew 7 лет назад

There are a lot of different designs that you can find online, depending upon the frequency range that you need to sweep across. Here are several links to get you started: www.nutsvolts.com/magazine/article/december2013_Reed www.vk2zay.net/article/93 www.ssl.berkeley.edu/~mlampton/oscillator.pdf www.dxzone.com/catalog/Technical_Reference/Test_Equipment/RF_Sweep_Generator/

@emprooney27 10 лет назад

Sir, can we use the same logic to sweep frequencies from 1KHZ till 3 MHz? and can u please help with the circuit to generate the same frequency sweep generation using opamp and 555 timer?

@w2aew 10 лет назад

This circuit was designed to be used with a VCF input of a function generator in order to generate a frequency sweep from the function generator. 1kHz to 3MHz is a very wide range for a voltage controlled oscillator, and would not be a simple circuit.

@Raldenaldrin 8 лет назад

Good day sir! i have Agilent 811A4 pulse generator, i want to have an automatic variation of frequency from 2hz-1000hz, may you provide the schematic diagram of the sweep generator? thanks!

@w2aew 8 лет назад

The only way I see to do this would be to provide an external trigger pulse whose repetition interval is sweeping. This won't change the pulse width, but will change the pulse repetition frequency. A ramp circuit like this can be used to control the charge rate on the timing cap in a 555 circuit, thus creating the required trigger signal.

@ediasjr 9 лет назад

Nicely explained. Thank you!

@raffyturc 2 года назад

hi Alan, stumbled upon your circuit while searching for a 'voltage controlled current sink'(for use on XR2206) sweep from 100KHz~900KHz, and found this. but I used a 4046 for freq sweep. VCCS is a bit over my head at the moment. anyways, it worked pretty well with 4046 vco though. thank you! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YVOu2RWBtuo.html

@jonaoconnor8065 5 лет назад

Could you make one that works on 220V rectified - 600V DC?

@Valenorious 11 лет назад

Thanks for the answer. Could I suggest the next circuit fun example? diy-VCO ;)

@hlmco 11 лет назад

Very well explained Sir, thanks!

@jonaoconnor8065 5 лет назад

This is perfect for a QCW and a PLL DRSSTC as fock dude, could you make this drive for 300 to 450 volts? @ 10/20Amps? Wouldn't be to hard to just amplify this signal...

@w2aew 5 лет назад

I don't have any experience in SSTC circuits or techniques, so I really can't help.

@peternilan4276 4 года назад

Alan is it possible to get a printable schematic diagram for the ramp gen ???

@w2aew 4 года назад

As with most of my videos, a pdf copy of my notes and drawings is available in the video description.

@peternilan4276 4 года назад

@@w2aew thank you for your reply i have now printed the circuit diagram thank you very much Peter/G0LVG

@gurudattsharma4560 5 лет назад

Can this ramp generator be used to trigger an SCR?

@w2aew 5 лет назад

A bit overkill, but sure.

@hermiloacosta8394 8 лет назад

It would affect if I use a 2n2222 instead of the 2n3906? Both are pnp

@thenextherobrine1764 8 лет назад

no, the 2n2222 is npn, it won't work

@UdiIsReal 4 года назад

I never looked into it, but now i finally understand what the vcf is useful for. Thank you so much!

@ohmedarick1 7 лет назад

I'm looking to build a basic function generator capable of sine wave, Square Wave, and Saw wave up to max 1 Mhz; 3 Vpp max output , input impedance of 50 ohms. can you please suggest one for me. Thank you

@w2aew 7 лет назад

There are several

@ohmedarick1 7 лет назад

Thank you for your response. I'm currently living in Guayaquil Ecuador.. It is expensive to send items from China or USA via Mail. But, I can I find very affordable semiconductors parts to build one. Have a great day and has always I learn and enjoy by watching your videos.

@Tesla210 9 лет назад

Is there a way to trigger the ramp or add duty cycle to this circuit?

@w2aew 9 лет назад

Yes, the trigger I out on the 555 can be used to trigger the ramp, just like any other monostable application of the 555 timer. The circuit is configured as an astable oscillator, being self triggered. You can disconnect the trigger from the Rest of the circuit and drive it as required.

@JustinAlexanderBell 8 лет назад

Working on a QCW coil?

@Tesla210 8 лет назад

Yes, Trying to build a ramp generator section that doesn't require writing code.

@TeslaExplorer 8 лет назад

did it work?

@nathanpc 11 лет назад

Another great tutorial. Thanks very much for the great content.

@raguaviva 11 лет назад

could I use this to create a vco?

@jamestheonas7831 4 года назад

There are a number of adf4351 sweep generators on the market and It would be awesome if someone could add a ramp generator output that coincides with the sweep time!

@w2aew 4 года назад

Shouldn't be too hard to do - the VCO tune voltage is available on one of the device pins...

@HitAndMissLab 7 лет назад

what about the reverse, or the ramp down circuit from 555?

@w2aew 7 лет назад

The output of the first op amp stage is the reverse signal, so you can use that, or buffer that with a non-inverting buffer/amplifier.

@MYNICEEV 11 лет назад

Brilliant. Many thanks.

@w3vjp568 7 лет назад

Do you have suggestions for a DIY voltage-controlled sinewave generator that this circuit could be merged with, to create a simple all-in-one sweep generator?

@w2aew 7 лет назад

Not off the top of my head, but I'll keep it in mind.

@w2aew 7 лет назад

@w3vjp568 7 лет назад

Thanks, awesome links! I particularly like the audio sweep oscillator. It's similar to an idea I have been thinking about cobbling together. I am playing around with the idea of using a 556 dual timer to generate a voltage-controlled square wave, then running this through a dual op-amp to integrate this into a triangle and then a (pseudo) sine wave.

@w2aew 7 лет назад

Just remember that when using an integrator to make a square wave into a triangle wave, the triangle wave amplitude will be proportional to the frequency. Fine for a single frequency, but won't work well for a sweep (unless you follow it with a voltage controlled gain stage to compensate - tricky.

@fromeijn 11 лет назад

thanks, learned a lot, maybe give it a try, sadly I have no function generator (yet)

@beehive808 11 лет назад

Another great tutorial, Just want to ask, how can you add adjustable frequency makers that show up the the scope when it sweeps. Thanks

@Zikeyboy101 7 лет назад

hello, how do i generate a negative voltage to power pin4 of opamp?

@w2aew 7 лет назад

It's usually done with a negative power supply. However, in many cases, you can get by with a single supply and simply shift the DC operating point of the circuit. You might find this video interesting: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-MtccB9K09ck.html

@lllmmm541 5 лет назад

thank you so much

@mcmadzima1200 5 лет назад

this is amazing, thank you so much

@amikhimji 10 лет назад

Great video thanks

@SimpleEnough2k9 11 лет назад

Found them, thanks. Now I'm checking if there are other valuse

@yuseffnehru8612 Год назад

Thank you for this feeds

@raguaviva 11 лет назад

Do you have any nice and simple circuit in mind? I'd like to check it out :)

@ferriswhitehouse1476 7 лет назад

Is there a good way to put dead time in there?

@w2aew 7 лет назад

You could set it up as a mono-stable, and trigger it with a second 555 (or use a 556).

@ferriswhitehouse1476 7 лет назад

great idea, thanks a lot! ill give it a shot.

@raguaviva 11 лет назад

great tip!

@truchuynh53 6 месяцев назад

Can i use lm393 for single power?

@w2aew 6 месяцев назад

I don't understand your question.

@truchuynh53 6 месяцев назад

@@w2aew Instead of using a dual -9 0 9 V source, can I use a single source opamp?

@w2aew 6 месяцев назад

@@truchuynh53 The LM393 is a comparator with an open-collector output, it is not an op amp. However, you can use any rail-to-rail op amp and run single supply. You may need to adjust a few resistor values.

@konshnakornnukua6701 7 лет назад

thank you very much^^

@bvspragathiengineersadda1116 5 лет назад

The constructed circuit works as shown #BVSPRAGATHI

@stoneslice 11 лет назад

Another outstanding circuit and video. Thanks. M6MKG

@danielghani3903 Год назад

May Allah bless you

@GeorgeGraves 11 лет назад

I think I found them Bourns 3386P-1-102TLF

@SimpleEnough2k9 11 лет назад

... values beside the 10K ones.

@notfallmed 10 лет назад

op thx DO 5 Net 73 Peter

@1903A3shooter 11 лет назад

Great and fun. W4GSM

@almostengineering1929 6 лет назад

"how hard is meteor"

@oddity2771 4 года назад

Fluxable

@wilmdrdo1228 6 лет назад

Can it be used for a narrow frequency sweep? For example a centrer frequency operates at a base 40 kHz frequency and a 4 kHz sweep (+ 2 kHz and - 2 kHz).? also do you haave a formula for that? thank you!

@w2aew 6 лет назад

It all depends on the VCO that you're hooking this up to.

@wilmdrdo1228 6 лет назад

what do you mean? Can you explain a scenario where it would not be applicable. thanks.

@w2aew 6 лет назад

This circuit doesn't generate the frequency sweep itself - it only provides the voltage ramp signal that is then used to drive the VCF (voltage controlled input) of a voltage-adjustable oscillator or signal generator.

@wilmdrdo1228 6 лет назад

Hello! I just built the circuit on the breadboard and it works fine except for when I adjust the gain the ramp grows in both direction. How do I fix that? Thank you!

@w2aew 6 лет назад

At 3:20 in the video, I describe the selection of the ** resistor to provide the appropriate offset to ensure that the signal at the output of the first op amp stage starts at ground - this should address your issue.