Interference from high voltage power supply (EHT power supply)

high voltageinterference

In class today our physics teacher was demonstrating how ionic fluids move when a high voltage exists between them. A USB microscope was placed above the test rig, and the image was projected onto the virtual board. He used a 500V-5kV supply, limited to 60µA. The demonstration was interesting, but more interesting was what happened when he turned the supply voltage up: the image on the board began to flicker, then broke up completely and eventually "no signal" popped up. It also caused the USB microscope to reset.

I'm thinking it was interference, but how could a high voltage but low current supply cause such problems for the projector?

I think it might be related to my digital clock having difficulties (resetting, alarm going off randomly, time skipping several seconds at a time) when it is within about 10 cm of my plasma ball, because both use high voltages.

Any ideas?

Best Answer

Its not a result of the high voltage but rather a by product of how that high voltage is generated. Very high frequency switching is used, such devices often emit a ton of RF around 25Mhz depending on the design. This is what throws off the USB scope and other digital electronics.

As for the whining your heard, plasma can actually transfer energy to the air very effectively. If fact you can even build a tweeter from plasma generation.

Incidently be careful with that stuff, ionizing the air into plasma generates a fair amount of ozone which isn't good for the lungs.