It is known that the plasma globes is the source of electromagnetic interference (EMI) and RF voltage that may damage nearby electronic
devices. In this plasma ball (made of 200W incadescent light bulb), this
problem solved by its shielding. The bulb is inside a grid made of thin
wire, which is connected to the ground terminal and the common circuit. It also increases the intensity of the sparks and affects
their color. They are orange instead of blue-violet. Such plazma ball really
does not emit any electromagnetic noise. The neon bulbs don't light up near it. The disadvantage is just that
the arcs direction can't be controlled by a finger.
The power supply is similar to the High frequency high voltage supply, but it has a lower number of turns on the transformer secondary, giving a lower voltage. Because of lower internal capacitance og the transformer I used the resonant capacitor 1nF. switching transistor can be any N-MOSFET with minimum 5A allowed current and voltage 100V, eg IRF530, IRF630, IRF730. The transformer is wound on a ferrite from high voltage transformer from an old CRT TV. primary is wound using wire around 1mm diameter, secondary using wire 0.3 mm (diameter is not critical).