A function generator is usually a piece of electronic test equipment or software used to generate different types of electrical waveforms over a wide range of frequencies. Some of the most common waveforms produced by the function generator are the sine, square, triangular and sawtooth shapes. Function generators are used in the development, test and repair of electronic equipment. The classic analogue ICs to build function generators are the Exar XR2206 and the Intersil ICL8038 integrated circuits, which can generate sine, square, triangle, ramp, and pulse waveforms at a voltage-controllable frequency.
I have very many years ago built a function generator using ICL8038 IC. That circuit has become slightly unreliable over the years, and I though of maybe having a newer function generator circuit. Instead of building a circuit based on plans like XR-2206 5Hz to 300kHz Function Generator I deviced to save some effort… I found a cheap kit XR2206 Function Signal Generator DIY Kit Sine Triangle Square Output 1HZ-1MHZ that seems to suit for me well. Specifications:
Voltage supply: 9-12V DC Input
Waveforms: Square, Sine & Triangle
Impedance: 600 Ohm + 10%
Frequency: 1Hz – 1MHz
The kit arrived well packed and promptly. Everything was packed in a plastic bag that was on padded envelope.
Kit came with instructions that had full circuit diagram.
Board seemed to be of decent quality.
Next task was to add components to the board. The components were in their own plastic bag.
Next task was to built board. It means putting the components to the right places on the board and soldering them. There was some confusion on the instructions over the electrolytic caps (do not go by the photos) the hashed marking is negative corresponding to the negative bar on the cap. After some looking it was clear that the shaded areas of the electrolytic capacitors on the PCB are connected to ground (minus).
The case came in parts that look like they are laser-cut acrylic plastic with protective film.
Next picture shows the ready case. The package has 8 screws, but I only needed half of them: The four small screws are not needed as the assembled case holds everything tightly.
The original case was planned to be transparent acrylic case. The plastic has protective film on both sides of it, that was designed to be removed when building the case. I somehow liked the look of the protective film, and instead left the film in place to get this look.
Nice, small, uncomplicated function signal generator. It is cheap and simple but worth the money.
Can be recommended for soldering practice, learning, and DIY applications. Good addition to a lab.
As mentioned on some product comments, there is instability above 12 volts which I will investigate as the function generator IC should work up to 26 volts by the datasheet.
Works up to 1.2 MHz
Signal (sine wave) can be adjusted from around 0.5Vpp to 4Vpp (higher than that settings distort waveform).
The sine wave signal is a around 4.5V DC potential.
More specifications:
SINE wave:
Amplitude: 0 – 3V at 9V DC input
Distortion: Less than 1% (at 1kHz)
Flatness: +0.05dB 1Hz – 100kHz
SQUARE wave:
Amplitude: 8V (no load) at 9V DC input
Rise Time: Less than 50ns (at 1kHz)
Fall Time: Less than 30ns (at 1kHz)
Symmetry: Less than 5% (at 1kHz)
TRIANGLE wave:
Amplitude: 0 – 3V at 9V DC input
Linearity: Less than 1% (up to 100kHz) 10mA
Product link: XR2206 Function Signal Generator DIY Kit Sine Triangle Square Output 1HZ-1MHZ
13 Comments
Sverre Holm says:
Interesting. I’ve just ordered one, so I can continue my experiments with the XR-2206 as a local longwave transmitter, like here: http://la3za.blogspot.no/2015/03/low-power-longwave-transmitter.html
Sverre
Tomi Engdahl says:
ATtiny85 Function Generator with OLED User Interface
https://blog.hackster.io/attiny85-function-generator-with-oled-user-interface-5280166b69a0
If you need to generate functions like square and sawtooth waves, you could buy a piece of equipment that will likely do the job quite well, or you can build your own.
Tomi Engdahl says:
Design errors in an XR2206-based function-generator from Ebay
https://www.youtube.com/watch?v=f_gnoU22Dj0
Roger takes a close look at an unbelievably cheap XR2206-based function-generator including an acrylic case-kit from EBay. This kit is probably the record-holder in design-errors per component-count
Most of them can be easily solved.
Fixing the issues with the XR2206 Function-Generator from EBay
https://www.youtube.com/watch?v=02XtneCHnDA
This video is about how to fix them and make a really useable mini function-generator out of the badly designed 7$ Ebay XR-2206 kit. A user has commented that the used XR-2206 is probably a counterfeit chip. This is confirmed here live by exchanging the chinese-supplied XR-2206 chip with a genuine one.
Tomi Engdahl says:
Download of the schematics with the optimized components and instructions:
https://www.youtube.com/redirect?v=02XtneCHnDA&event=video_description&q=https%3A%2F%2Fwww.kainkalabs.com%2Fupload%2Findex.php%3Ff%3D158f92d8d08e51&redir_token=8Vi90vWSlwMAxGJgWbHM9w5GZpF8MTUyNzIzMzEzNkAxNTI3MTQ2NzM2
Tomi Engdahl says:
#97 Simple function (signal, waveform) generator
https://www.youtube.com/watch?v=LTe74zH9A6E
XR2206 Function Generator Project – Build a cheap, simple function (signal, waveform) generator.
Here’s an uber simple project for generating square waves, sine waves and triangle waves, ideal for general electronics use and for use in Arduino projects too. A simple project like this is also ideal for electronics beginners, with limited soldering skills.
This description (and ALL links) is repeated here:
https://github.com/RalphBacon/XR2206-Function-Generator-Project
Build a cheap, simple function (signal, waveform) generator (not a sponsored project)
Tomi Engdahl says:
XR2206 function generator kit tested
https://chinese-electronics-products-tested.blogspot.com/p/geekcreit-xr2206-function-generator.html
Tomi Engdahl says:
ICL8038 function generator kit tested
https://chinese-electronics-products-tested.blogspot.com/p/icl8038-function-generator-kit-tested.html
Tomi Engdahl says:
Function generator without special generator IC
Improved DIY Function generator project
https://www.gadgetronicx.com/improved-diy-function-generator/
a DIY Function generator that can produce Square, Sine and Triangle wave with adjustable frequency. This project is a improvised version of DIY function generator which was published in our website earlier. Unlike the previous version, this FG comes with logarithimic sine wave converter and improved efficiency.
Tomi Engdahl says:
https://labprojectsbd.com/2020/04/13/function-generator-with-icl8038/
Tomi Engdahl says:
https://hackaday.io/project/163565-lissajukebox-aka-dedicated-lissajous-machine/log/158895-modifying-the-xr2206-kits#:~:text=The%20XR2206%20is%2C%20according%20to,no%20longer%20made%20by%20Exar.
Tomi Engdahl says:
http://www.vwlowen.co.uk/arduino/xr2206/XR2206-function-generator.htm
Tomi Engdahl says:
I don’t know when the XR2206 went out of production but apparantly it has. And all the cheap diy frequency generator kits from China use copies that aren’t very good or up to spec.
But can you still find og 2206′s? In that case, are there specific markings/letters to look for? I’m just scared of buying trash even if it’s not a lot of money wasted.
Source: https://www.facebook.com/share/p/qAr3atyKCMTRq5Wq/
Tomi Engdahl says:
Like most obsolete parts from the 1980s, these are rare to find now. Most of what are on the market are chinese copies. Apparently they do work, but not sure how good they are.
The design of the original IC was good in theory, but the practical side of them wasn’t that great.