# Charge / Voltage Questions

1. Oct 29, 2004

### hodges

I have a high voltage generator taken from an air ionizer ("negative ion generator"). I am able to draw approximately 1/8 inch spark between the HV lead and ground.

I had an idea to increase the voltage and length of the spark. Using a setup similar to a Van De Graaf generator in principle, I would place the HV lead inside a sphere. Ions should leave the HV lead, causing a negative charge to continuously build on the sphere.

So I cut the top off an aluminum soft drink can and bent down the sharp edges. I pushed the open side into an styrofoam coffee cup. I punched a hole in the bottom of the styrofoam cup and pushed the high voltage wire (with the end exposed) through this hole so the end of the wire is inside the can but not touching the metal on the can. Sure enough, I was now able to get longer sparks - nearly 1/2 inch long to the can and much brighter than the sparks produced using the ion generator alone.

So far so good. However, next I tried connecting the HV lead directly to the can, instead of letting the can be charged by ions. The result was almost identical. I got a spark nearly 1/2 inch long. The spark appears to be the same length and intensity whether the HV lead is inside the can (not touching), touching the inside of the can, or even connected to the outside of the can.

I have two questions. First, should I be able to get a higher voltage than that produced by the ion generator (limited only by the rate of leakage from whatever I use for a sphere) as I expect? Second, how am I also getting the same higher voltage with the HV lead connected directly to the can? How could the voltage on the can be higher than the voltage produced by the ion generator when they are connected together?

Thanks,
Hodges