Tesla Coil

High voltage discharges having an appearance similar to lightning can be obtained from a properly designed Tesla coil. The Tesla coil employs the principles of the transformer with a small number of turns on the primary and a large number of turns on the secondary. 具有类似闪电外观的高压放电现象可以通过精心设计的特斯拉线圈获得。特斯拉线圈利用了变压器的原理，其初级线圈的匝数较少，次级线圈的匝数较多。

The large Tesla coil shown above is part of a demonstration show called "The Wonders of Physics" by physics professor Clint Sprott of the University of Wisconsin. The primary consists of a small number of loops made from a large conductor. The secondary has a large number of turns of small wire. The high frequency input to the primary coil is transformed up to about a million volts, and therefore the current is very small. The high voltage is enough to produce spectacular electric discharges like those shown below.

One of the predictable things about such discharges is that they are unpredictable! The variety of discharge patterns above were obtained in less than a minute. This was in an auditorium where the conditions of the air around the Tesla coil were fairly stable. This is an example of a chaotic phenomenon. It illustrates the futility of trying to predict the path of lightning strikes, since there are many more variables in that case.