What is the difference between alternative current and continuous current?

A modern violet wand typically consists of a hand held "wand" made of plastic. The base of the handle has a permanently attached electrical cord which plugs directly into a wall outlet. The wand will have an intensity level control and sometimes an on/off switch, usually located near where the electrical cord is attached. In the base of the wand, an electromagnetic "buzzer" type circuit rapidly makes and breaks the circuit, thus serving the purpose of a spark gap in a normal Tesla coil. The intensity is controlled by varying the distance between the electrodes, and thus the intensity of the output (a key difference between a violet wand and a normal Tesla coil is that as the output of a violet wand increases as the distance between the electrodes decreases). The electromagnet also serves as an inductor to prevent the unit from drawing too much current. The Tesla coil consists of two coils and a capacitor. The "tip" of the wand (the output of the Tesla coil) has a socket into which an electrode is inserted.