The simplest and easiest way to generate ions is to use a Cockroft-Walton multiplier circuit. This is a string of diodes and capacitors in a succession of voltages doubling circuits. The diodes and ceramic disk capacitors are readily available components with a high long term reliability.
NOTE: this project MUST be mounted in an enclosed box or container for THREE reasons:- the first is that it is AC powered. It must be kept protected from people accidentally touching it. The AC cable must be firmly secured by the usual means. - second, is that it has a chain of voltage doubling circuits. At the end of the chain (at C30) you do not have to touch a component to get a shock. A spark will jump across about 3mm to get you. (The shock is really just a tickle and it is more a surprise than anything else.) - third, the final stage of the ion generator - the three resistors and the pin farm - must be suspended in the air and not near or touching a solid surface. Ions are funny things. At the high voltages but very low currents available the ions will collect on particles (dust) and solid surfaces. If the pin farm and protection resistors are on a surface (plastic, newspaper) the ions will not be generated.
The PCB is 2 inches x 4 inches
Also note that if you are sitting in a well insulated, dry chair then there is no shock if you accidentally touch the pins on the pin farm when the generator is in operation. You do not have to worry that when you listen to the ions being generated that you will get a huge shock if you accidentally touch a pin. We are not suggesting you deliberately start feeling the pins. And do not touch the components in the doubling chain what ever you do.The circuit as presented is designed to generate negative ions. However, by simply reversing all the diodes, D1 to D30, in the ladder you automatically make it into a positive ion generator. This gives you an easy way to test for yourself whether negative ions and/or positive ions affect mood, performance etc. You may buy two of these kits and construct one as a negative ion generator and the other as a positive ion generator. Then put them in different situations either with or without people knowing. Leave them on for several days and note any changes or alteration in behaviour. ARE NEGATIVE IONS OF BENEFIT TO YOU? Quite a bit of research has gone into this topic. Research ranges from the pseudo-scientific to the reputable. A list of some papers from the latter group is given here. In summary, there is no evidence that negative ions have any effect on well being however it is defined. The claims by commercial producers of negative ion generators that their products enhance efficiency, increase productivity and contribute to personal health are unsupported by scientific evidence. However, if you think something is going to do you good then it may in fact do so; this is the placebo effect. And a lot of research in the 1990's has gone into it.
Recommended box: FB04