I'm using a microwave oven transformer for some high voltage projects including testing it out with some voltage doubles. I ran into a rather curious problem I dont seem to understand and I'm just hoping some one can explain to me what is happening. So I built the double like this:
When I connect the high voltage AC to the correct spots (in between the caps and in-between the diodes) It appears to double the voltage and the length the spark could jump. I wanted to verify this was the case and so i took the lead connected to the diodes and held it just off the other end of the bottom capacitor (as in the pic). As expected, the spark was half the length. However this is the odd part. My capacitors are ceramic disks rated for 10'000 volts and at most the double produces about 5000 volts. However after arcing for just a few second that spark jumped from the upper most lead on the top capacitor the the bottom most lead on the lower capacity. Thats a gap of about inch! Way more than 5000 volts! So I'm just wondering why this happened? I didn't get to do more testing because the cap that wasnt being used (the top one) broke down and failed, but the bottom one is fine. Can any one explain that happened here?
Edit: I added my own picture of what i was working to be more helpful. The "little spark" is where i was testing to see if the distance/voltage actually increased (and it did, in the configuration shown the spark is half the distance than in the proper configuration). This big "whats going on" spark is, well, the whole question. Also, the "little spark" was much closer than pictured. it was about 1mm but the big spark is just as shown.