james holden

There was just a thunderstorm here this evening, so the air’s nice and clear now after a few days of humid, oppressive air. It got me thinking though, about an old ioniser we used to have when I lived at home. I think I’ll build one this week. All you need is a Cockroft-Walton multipler driver straight off the mains. 25 stages should give about 17kV which will produce a nice effect. I’ll pick the bits up from Maplin tomorrow and build it this week.

They’re dead simple to make. All the capacitors are 100nF polys and the diodes are 1N4007 rectifer types. It’ll cost about a fiver to make, plus a box to put it in. Not all the stages are shown below. An extra 10M resistor across the input might be an idea, to prevent getting a zap from the mains plug.