flourescent bulb powered by h.f

[saltukhan]

some say that when a high frequency source gets near to a flourescent lamp it makes the lamp work ,so is it true and if so what is the principle ? magnetic field or electric field or frequency?

 

[PHovnanian]

Its about the electrical field strength. Hold a fluorescent lamp near a high voltage 60 Hz line and it will light as well. Its just easier to generate the necessary field strength with a shorter wavelength (higher frequency).

While dry air has a breakdown voltage of around 3x10^6 V/meter, the breakdown voltage needed to strike an arc in a fluorescent lamp is on the order of a few hundred volts per meter.

 

[bartb102]

Yes, high frequency power can excite a flourescent tube without any connections. While in college I worked on a heat sealing press making vinyl notebooks. Energy source was a 10KW RF transmitter operating at 25MHz. We typically placed a 20W flourescent tube across the upper platten to indicate when the power was on. In the time before OSHA you learned quickly to not touch the platten when it was on. I can still feel the burn on my finger tips. It took only 3 seconds to fuse three layers of vinyl. To add injury to the insult the top platten fell off and landed on my hand while I was loading the next notebook.

A friend built a Tesla coil and would light a 30W tube by holding it near the coil.