Maker Lab #1 Analog Signal Generators: XR2206 vs ICL8038 

The XR2206 sine is CRAP!!!!!!!!!!!! Use the scope FFT and you will see it has pile of harmonics that should not be there!!!!!!!!!!

The XR2206 has jitter problems above 12V and the increase in amplitude that you get is minimal. That is why they suggest to use 9-12V

Great presentation, thanks!

Very good comparison of those two cheap modules. I wanted to play with them but I choosed XR2206 one just because many years ago I made a quite complex function generator with few of them (it had AM, FSK, sweep). Altough is a clone (fake) IC, is pretty good if you know what to expect; i mean for audio frequency is almost perfect. And that if you work clean and make some improvements. I built my kit but used a symetric power supply +/-5V (the output is ground refferenced, no need any capacitor to block DC). I also used a multiturn potentiometer to adjust the frequency instead of those fine and coarse ones. I borrowed from datasheet the symmetry circuit and I think that I improved the circuit quite a lot. For sure, the sine wave is not perfect, but for audio (and beyond, up to 150KHz) is very good. As for the square wave, I used a 7414 to have a proper TTL output.

Great video, i remember messing with XR2206 and a speaker until i got my LFG-1300s Cant wait to find more videos from you, you seem funny and relatable

Nice wit some DX music in the background :D

OK VERY Good❤❤🙏

XR2206 would surely do for audio work? I do a lot of mixer, transducers, valve/tube amps etc! Excellent presentation ! Fraser

Great video, I believe it is harder to get cheap electronics parts in Brazil compared to my home (UK) and so this is a great idea, keep up the good work Sir ! might be interesting to use the 'Math' function on your Rigol and have a look at the FFT for the Sine Waves as this would reveal all !!....If you want a very clean Sine and a bit of theory thrown in for good measure you might try looking at 'Wien Bridge Oscillators' fun to play with and can achieve THDs below -60 dBm...cheers.

You don't need to use hot glue. You have to mount 4 short screws in the corners of PCB, than nut on the oposite side of PCB act as a distance and thats it. No need to screw PCB into the backplate. Then you just lay it loosely on a backplate, with the ends of the screws in the holes and mount the rest of the enclosure over it. When you finish, everything will stay solid. Just remember, to mount capacitors horizontal, other way it will be a little tight.

You must be a Deus Ex fan, ...could not help but notice the background music! :)

Your square wave would likely be a bit better, if you would set the probe to x10. The x1 mode has too much capacitance that together the pull up resistor slows down the positive transition.

Does the triangle/sine output work better if the square output is left open? And are the voltage and current in phase? 🤔 (For the xr)

Hi! How did you load the gen for your test? I got trapped and got weird things bcse I frogotmy scope loads about a megohm and got weird sigs. Terminating with 50 ohm should be OK though I ain't got a clue what the actual output impedance is. You get what you paid for and as long as you got a scope, you can use it . Remember offset will cause sig to clip depending on amplitude. Take caution when DC coupled, current might not be limited and you may fry your board. Ask me how I know. My 2 cts. Antoine, operator of F8EBL station.

I find it easier to solder the small components 1st. Nice video, maybe leave the background music out..👍

These chips must be made by Chinese 3rd party makers. The original chips are old ! 1970s old. I made my first function generator with the original Intersil 8038, back then, while I still was a poor kid in high school. Don't know much about the Exar part (XR2206), but the 8038 uses the triangle wave and applies to a "piecewise linear network" to form the sinewave. Its not the best. Many years later, in the 1990s, to get a cleaner sinewave, I use a multi-stage switched capacitor filter, to filter a squarewave into the sinewave. These switched cap filter's cutoff freq are either 1/50 or 1/100 of the filters clock frequency. So you make a your "clock", and divide it by 100 (or 50), and apply both to the switch capped chip, and get a nice sinewave out. Recently, I've been getting back into tubes, and just made a Wien bridge oscillator. Simple. Two tubes, and an old fashion 5W incandescent "nite lite" bulb. The bulb is a non-linear resistor, and it only sees a couple of volts. Nowhere close to its rated voltage, so it should last forever.

On the 8038 kit a jumper is labelled SIN or TAI. I kept thinking "What is TAI" until I realized it is a typo and it was supposed to be TRI. Kits of this type are made as cheap as possible and are typically based on the example circuit shown in the datasheet. Some years ago I saw a circuit using the 2206 that got better results from the chip by wiring things up based on a better understanding of how the chip operated. I have a document for a very capable signal generator project using the 8038 that goes much beyond the version shown in this video. In general, the 8038 is the better chip. It is all in how you use them that will determine the type of results you can get from using either the 8038 or the 2206.

What is minimum and maximum amplitude of sine wave?

Wiki says the 8038 was discontinued by the manufacturer in 2002. I would guess the reason it is so cheap is the Chinese copied the chip since the IP was so old and the chip so simple to make then they would be paying pence for it. China uses a lot of these old chips. They have their uses if you just want standard performance, but not really what you would use for test equipment.

As I saw in another video for these kits, one of the pots is not like the others and can do what you are showing. Might just be a crap kit also.

Le xr2206 est vieux, très vieux... Je constate que produire une sinusoide reste problématique dès lors qu'on veut modifier l'amplitude ou la fréquence : Rien de nouveau hélas dans ce domaine Grand Public. Pourtant On sait faire mieux...

Mmm, Deus Ex music.

Negative offset is fine and expected for a function generator. The Arduino monkey-see, monkey-do types you speak of need to learn some electronics and they'll get by a bit better. You also have to be aware of few things. First, these are not DDS generators and being cheap little singe chip generators that do so much, you can't expect them to produce the same performance you'd get from a real instrument. Next, given the price you paid these are, with almost 100% certainty, counterfeit chips that DO NOT work properly. Also, the XR kit has a positive offset you can't remove. To me, that's a total fail. I would prefer a "real" ICL8038.

It sure took you long enough to stop that scope waveform from rolling like it was for a while there... Some years ago I wanted a function generator, so I decided to build one. Way cheaper than what I would have had to pay to buy one in those days. I see where these days they seem to routinely go up to 1 MHz, but for me the audio range was going to be good enough. The ICL8038 would go 20 Hz to 20 KHz without any sort of bandswitching, which is what I wanted. I could not see a way to do this with the XR2206, which I am seeing much favored by the chinese vendors these days. I did build it, powering it with a dual-voltage power supply regulated with a couple of zener diodes (probably an area for improvement) and also have provision for applying a DC offset to the output signal. I intend to provide a TTL-compatible output but didn't have the right buffer chip handy to do that so the BNC connector is there but not presently connected and I haven't missed it. I also have not included any provision for varying the duty cycle of the waveform. For the most part it works well but when you get really low in frequency the sinewave goes to shit. Maybe one of these days I'll figure out why that is...

how did you get a visa to brasil? are you rich?

The voltage limits on the XCR2206 is because the XR2206 chip is a FAKE that cannot handle the full voltage range.

You might be interested in XR2206 design errors video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-f_gnoU22Dj0.html

MAX038 based is way better (goes to 20Mhz). :)

The ICL8038 kit is using op-amps way too low bandwidth & V/uS ability! Crap design as expected! :(

Wow, even the ICL8038 is CRAP for operation! I think the Chinese need better design engineers. Sadly these bad designs are typical for Chinese stuff. :(

The saturation and general NO trust of control is CRAP CRAP CRAP CRAP CRAP!!!!!!!!!!!!!!!!!!!!!!!!