Signal Generator Kit, XR2206 Precise Function Signal Generator Frequency Module DIY Kit Sine Triangle Square Output Adjustable 1Hz-1MHz, 9-12V Direct Current Input(1 Piece)

Beware of the value of R4. That resistance controls the shape of the sine wave. 330 ohms is too high for my chip, so the sine wave was still too triangular. 220 ohms did better. If this is for having a second signal generator for breadboarding, you already have a breadboard, and should find an appropriate value for your chip, before soldering onto the pcb. I also skipped putting C8 in parallel with C7. C7 alone was fine enough for my needs.The value of C1 is depicted as 100uF, but tabulated as 47uF. The kit came with 47uF, and it's just a filtering cap, so it's fine.The XR2206CP itself comes off the pcb, so I can use it on a breadboard for other bands, pulses, ramps, fm, or am, as needed.Still five stars, despite the above caveats, because I have a breadboard, and a 220 ohm resistor to swap. Take away stars as needed if you don't.

The maximum frequency for the unit that was delivered to me is only 85 kHz. (I can measure it with my oscilloscope.) I compared the printed circuit board that I have to the one in the pictures on Amazon. The one pictured on Amazon has five frequency ranges while mine only has four. Maybe the missing one is the higher frequency range? Also, the plastic box seems unfinished. While the box is transparent in the Amazon listing, the one I have is not, and it does not have the labels on it for the frequencies.The function generator chip on this board is the XR-2206. It lets you set the output frequency using external capacitors. The data sheet gives the formula for the output frequency and from the component values in the circuit, the max output frequency will be 85 kHz. So, that is consistent with what I measured. It can go to higher frequencies, so I might replace some of the higher value capacitors with lower valued ones that will result in higher frequency output.The output sine wave has a DC offset of 6V if you supply the circuit with 12 V. I think if you supplied it with +/-12V it would be centered at 0V.I bought this to generate a sine waves from 20 to 40kHz, so it's fine for my purposes. It;s pretty cheap too.

I ordered 2 of these and both had issues. One had components with no markings or labels on them at all and the second one had bent pins on two of the chips and a broken piece of the frame. Would not buy again nor recommend to anyone.

What a great little box! I bought this to help test an older oscilloscope and to learn on. I asked a question and got an immediate and correct answer. The build took me a couple of hours. I am impressed with the range on the controls. Only caution is it is very small and there are some tight spots where you have to be careful to not get too much solder in there. But take your time and be neat about it and it will all work out. It’s a fairly easy build and a robust design. I will say the triangle wave form looks better than the sine wave, but for my purposes, it’s really good.

All in all, not bad and well worth the price. It was a fun build with a few head-scratchers along the way. See below.Was favorably impressed with the engraved labels on the bottom surface of the case top. They're easily legible and are quite well done considering the small text size.The finished device does pretty much what the descriptions and specs indicate.While I'm satisfied, there were a few things that could have been better. None were fatal and all were relatively easily corrected. The solutions are out there, or in here if I caught everything.Assembly:- Documentation (one small, two-sided, ninth daughter of a Xerox page) print quality was abysmally bad. Text was readable, barely, including the parts table but the schematic was completely illegible. Before doing anything with this kit, go here...https://helpfulcolin.com/xr2206-function-generator-kit-improved-instructions/...for a third party page with very good instructions and images, including a clean version of the schematic, board photos, etc. It's a vital resource for working with this kit.- The board symbology for the electrolytic caps C1, C3 and C4 shows a circle with one half shaded. I was not familiar with that symbology but was finally able to work out that the shaded side of the circle indicates the negative side of the capacitor (for this kit - may not be universally true). The short lead and white stripe on the cap go to the shaded side of the circle.- 1K resistor missing. Since I had a seabag full in the parts box, not a real problem. In return, I got an extra M3 X 10 mm screw and nut, so I consider it an even trade.Tip - I recommend that you solder the electrolytic caps C1, C3 and C4 laying down. I didn't and the top cover wouldn't go all the way down. Was able to fix it by bending C3 and C4 down but had to make a hole in the cover for C1. Was able to do that by hand with a 7 mm brad-point drill and a little file and hobby knife work. It's not too ugly and cover does go all the way down now.Function:Device does everything the specs and description says it does.- Obvious clipping of triangle and sine waves if the amplitude is too high but trimming them down with the amplitude pot produces fully formed waves.- As noted elsewhere, the sine wave is not a true sine wave. It's more like a triangle wave with radiused tops and bottoms. Sides of the waveform appear flat, not with the constantly changing slope of a true sine wave. Probably fine for most things.- Square waves show the effect of lagging rise times at higher frequencies, beginning at about 40 KHz. The left edge of the pulse is deformed near the top, grossly so in the highest part of the frequency range; the right edge of the pulse is perfectly square. Not an unexpected issue and like the pseudo-sine wave, probably OK for most applications.

No literature for user operation. No labeling on top plexiglass like shown in item sales page. Pretty easy to assemble but no assembly instructions.I tried to get information and all I got was a picture of assembly steps but had it together.