second chamber the diaphragm may have first and second positions or numerous variable positions applying a voltage across the electrodes may electrostatically move the diaphragm to the second position during which the outlet is at least partially opened for fluid communication with the inlet the orifice is closed and the diaphragm is stopped in the second position by a cushioning fluid pressure in the second cavity to prevent pull in removing the voltage from the electrodes may let the diaphragm return to the first position open the orifice and close the outlet application_number US 90599505 A description in an electrostatic modulator the electrostatic force may work against a force that keeps two electrodes of the actuator apart this force may be generated by an elastic force a pneumatic force or the like by applying a driving voltage the actuator position may be controlled one third of the initial distance between the electrodes and the then pull in snapping effect occurs this control may be done for a certain span of the driving voltage until the pull in threshold this threshold value may be small thus not offering a good resolution for the control driving voltage and making control difficult if the force that keeps the electrodes apart increases with the displacement of the electrodes the pull in effect may occur at one third of the displacement also but at a higher threshold value the higher voltage control.