Got me a USB plasma ball from Amazon.
It’s about the size of an orange. It plugs into your computer USB port for power.
It’s actually fairly bright in room lighting, but looks better in darkness.
If you can focus the camera, that is.
As you probably already know, when you touch it an arc jumps from the center to your finger.
Here’s a video in action:
You can buy one for $7.95 from Amazon here:
By the way, it will also run on a five volt ‘wall wart’ but you’ll need to buy one separately (assuming you don’t have a drawerful already).
I wonder if this could be powered by a 9 volt battery through a 7805 (ie, 5 volt) voltage regulator. Maybe I’ll try that, but I thought I would play with the plasma ball for a bit before I do anything that might break it.
UPDATE OCT 12: The plasma ball seems to be losing its strength. It still makes a visible arc between the center and my fingers, but otherwise it’s not that impressive to look at. Buyer beware, I guess.