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Main >> Applications >> Sample problems >> Electrostatic speaker

Electrostatic speaker

QuickField simulation example

Electrostatic speaker consists of a pair of stator plates connected to the audio amplifier and a metallized diaphragm connected to a high voltage source.

Problem Type
Axisymmetric multiphysics problem of electrostatics coupled to Stress analysis.

Geometry
Electrostatic speaker Electrostatic speaker consists of a pair of stator plates connected to the audio amplifier and a metallized diaphragm connected to a high voltage source. Stator Diaphragm V+ R +½·|V~| -½·|V~| 0 ~ Amplifier Stator

Given
Relative permittivity of diaphragm ε = 3;
Diaphragm thicnkess 40μm;
Power supply voltage V+ = 600 V
Amplifier output voltage V~ = 100 V, peak.

Task
Calculate the electric force acting on the diaphragm and diaphragm mechanical displacement.

Solution
To calculate the maximal displacement we should apply the peak value of amplifier voltage. In the model left stator has the potential of -½*|V~| = -50 V, and right stator has the potential of ½*|V~| = 50 V.
The forces distribution is then passed to mechanical problem to calculate the displacement.

Results
Electric force acting on the diaphragm is -0.014 N per 12.5 cm² of diaphragm area. Diaphragm central part displacement is 0.3 mm.
Electric field stress in electrostatic speakerLoudspeaker diaphragm displacement

Reference: Wikipedia: Electrostatic loudspeaker