Plasma globe
Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of multiple constant beams of colored light.
[1] The plasma lamp was invented by Nikola Tesla, during his experimentation with high-frequency currents in an evacuated glass tube for the purpose of studying high voltage phenomena.
Additionally, some designs utilize the ball as a resonant cavity, which provides positive feedback to the drive transistor through the transformer.
A much smaller hollow glass orb can also serve as an electrode when it is filled with metal wool or a conducting fluid that is in communication with the transformer output.
This single tendril's plasma channel engages enough space to transmit this lowest striking energy to the outside world through the glass of the ball.
[citation needed] The neon available for purchase for a neon-sign shop often comes in glass flasks at the pressure of a partial vacuum.
Of the other noble gases, radon is radioactive, helium escapes through the glass relatively quickly, and krypton is expensive.
By adjusting the voltage, frequency, chemical composition and pressure of gas in the globe, many colorful effects can be achieved In U.S. patent 0,514,170 ("Incandescent Electric Light", 1894 February 6), Nikola Tesla describes a plasma lamp.
He gained patent protection on a particular form of the lamp in which a light-giving small body or button of refractory material is supported by a conductor entering a very highly exhausted ball or receiver.
[1][3] These gas mixtures, along with different glass shapes and integrated-circuit-driven electronics, create the vivid colors, range of motions, and complex patterns seen in today's plasma spheres.
Plasma balls are mainly used as curiosities or toys for their unique lighting effects and the "tricks" that can be performed on them by users moving their hands around them.
However, in recent years, some novelty stores have begun selling miniature plasma ball nightlights that can be mounted on a standard light socket.
A step-down transformer connected between the plate and the ball's electrode can produce lower-voltage, higher-current radio frequency output.
The high voltage radio frequency energy coupled to them from within the ball may cause a mild electric shock to the person touching, even through a protective glass casing.
The radio frequency field produced by plasma balls can interfere with the operation of touchpads used on laptop computers, digital audio players, cell phones, and other similar devices.
