electrostatic loudspeaker
The structure of the electrostatic loudspeaker corresponds to that of a capacitor. Here, the loudspeaker membrane can be located between the two electrodes and controlled by the electric field; however, it can also be one of the electrodes.
In electrostatic operation, two electrodes with equal charge repel each other, while two electrodes with unequal charge attract each other. If a voltage is applied to the electrodes of an electrostatic loudspeaker, the voltage level is a measure of the deflection of the electrodes. A high voltage causes a large deflection, a low voltage causes a small deflection, and a reverse-polarized voltage causes a deflection in a different direction. The force acting on the electrodes depends on the electrostatic field constant, the plate area and is proportional to the square of the voltage.
Electrostatic loudspeakers are often designed as tweeters. However, with the electrostats, there is a loudspeaker design that covers the complete audible frequency range.