XR2206 function generator kit
The first things I noticed about this kit are the price and the finished quality. As you can see it comes with a Perspex enclosure and control knobs and is very complete for an inexpensive kit.
You get everything you need including nuts and bolts you just have to provide the solder and expertise. Speaking of expertise you will need some of this as the instructions are quite poor and a beginner would probably struggle. However for as poor as they are they are also amusing, well they were to me anyway. Probably the best line is “check the IC whether against, such as anti please timely correction” I’m sure Dr Who mentioned anti please timely correction in an episode.
If you are a beginner and you want to build the KKmoon XR2206 High Precision Function Signal Generator DIY Kit don’t worry I’ve put my own instructions here which I’m sure most people will be able to follow.
As you can see what you get is a small bag in a padded jiffy bag. Upon opening this in Russian doll style you find two bags. One containing the components and the other containing the perspex bits that make up the case and the red double sided PCB.
As you can see the perspex bits are covered in a protective brown paper that needs to be peeled off this is probably the hardest part of the construction to be honest.
You get a bottom plate, two identical top and bottom edge, left and right bits that are slightly different but I’ll come to that later.
Also included in this bag is the red PCB which is screen printed and double sided with plated through holes so no links to solder in.
Constructing the signal generator kit
You can see from the picture above the other components that are included. First you need to get the five resistors. Ideally you need to know the resistor colour code. If you don’t you can go to my colour code page here for help. If you have a component tester like this one here you can measure the resistor values. If you can’t do either of these things you can still identify them as resistors R3, R4 and R5 are all the same value so will have the same colours on them. R4 is 330R in value so will have a couple of orange stripes at one and. The other one is R1 which is 1K. Seriously though learn the colour code it’s easy once you know it.
The board has printed component locations so put them in and then solder them and trim the leads.
Looking at the instructions the component table is the only useful thing about them. Put the three polarised capacitors C1, C2 and C4 to one side and just concentrate on the smaller ones. These are all marked with the normal capacitor number codes but you may need a magnifier if your eyes are anything like mine.
C2 has 104 printed on it.
C5 has 105 printed on it.
C6 has 473 printed on it.
C7 has 222 printed on it.
C8 has 101 printed on it.
These can then be soldered in place and you should end up with something that looks like the picture below.
Next insert the IC socket with pin 1 at the top of the board and find C1 the electrolytic capacitor value 100uF. As this is polarised it has to go the correct way round. Look down the side of it and there will be a line indicating negative. The PCB has a shaded half which also indicates negative so make sure that lead goes there. C3 and C4 have the same value of 10uF and are also polarized in the same way so be careful to solder them in the correct way round.
With these parts in you should end up with a board like the one below.
Next put the jumper assemblies in, jack 1 for the DC power and the wire terminal connector block. This leaves the three variable resistors. R8 is marked B104 and R2 and R7 are the same value and marked B503. Push these firmly in place before soldering.
You should then have completed the board like in the picture below.
Next stage is to insert the IC. This is an XR2206 and is the main part of the kit. Pin 1 is at the top. Double check you’ve put it in the correct way round.
As there is no mention of any other construction I can only assume that you take the four short screws and put the nuts on the bottom of the board like the pictures shown below.
This will then fit in the bottom plate. The top edge and bottom edge can then be put in place. Remember at the beginning I told you that the left and right Perspex edges are different? Well you will now see why, one has a cut out for the blue terminal block. Once you have these in place you can fit the front panel on top. With a bit of giggling it will click in place then you put the long bolts in and these screw into the bottom plate holding the whole assemble together. The finishing touch is to slide on the control knobs and then you have finished.
DIY signal generator
So what are my impressions, the instructions are poor but if you follow the instructions above a beginner could easily build it. For the money you pay I can’t fault what you get. It looks good for a piece of test equipment and the case is excellent in making the device functional and keeping it all together and protected.
When you connect it up to power make sure the polarity is correct. It does adopt the more usual positive central pin and the specification says to use 9-12V. You need to be careful with what supplies you use. I tried a wall wart type power adapter and the waveform outputs were awful. I can only put it down to being a noisy and not smooth power supply. When I plugged it into a proper bench power supply everything was much better.
The square wave does not go through the level control. Only the sine/triangle is controlled by the level and even by varying the supply between 9V and 12V I couldn’t stop clipping occurring with the level control turned up.
Both fine and coarse frequency controls do their job and the range control works by switching in different values of capacitor.
So if you want a simple project that’s cheap and only takes half an hour to build this is for you. You’ll also end up with a useful addition to your electronics hobby.