How the speaker works
The essence of sound waves is the expansion and contraction of air to drive the surrounding air to produce propagation phenomena from near to far;
During arc discharge, the current in the arc will change the diameter (thickness) of the arc section;
In the general state, most of the air molecules are neutral and uncharged. But after high-voltage discharge, they become charged particles. This phenomenon is called ionization or ionization. The violent ionization process will produce arc discharge. The cross-sectional diameter (thickness) of the arc is proportional to the current in the arc. The thickness is the expression of the different degrees of air expansion. (The generation of sound waves requires the expansion and contraction of air. The contraction process is the arc The process of changing the air expansion coefficient from large to small, and from large to small) through audio signals to control the size of the current in the arc to generate corresponding sound waves, which is the principle of ion speakers.
Plasma speaker is a pure class A speaker, it needs a proper bias current to produce sound without distortion. The same as the triode bias: the audio current is directly superimposed on the bias current. Since the thickness of the arc has nothing to do with the direction of the current, the bias current can be either DC or AC. The selection of the bias point should satisfy: modulated audio After the signal: the minimum absolute value of the arc current is greater than the arc maintenance current.
High temperature and strong oxidation during discharge will damage the electrode, especially the cathode bombarded by positive ions. In order to minimize the electrode loss, AC discharge is often used. AC modulation will bring about the problem of sampling distortion. In order to minimize sampling distortion, To use a high-frequency baseband signal of 20MHz and above, and then modulate the audio signal (amplitude modulation)
