voltage required to open a normally closed valve in a high pressure fluid environment whilst ensuring relatively high flow rates through the microvalve once opened application_number US 4376102 A description for homogeneous dielectrics between electrodes the electrostatically generated force f e increases directly with the square of the voltage u applied between the electrodes and inversely with the square of the distance or gap d separating the two electrodes as stipulated in the following equation eq 1 fe 1 2 ue89e u025b u025b 0 ue89e a e ue8a0 u d 2 eq ue89e 1 where u03b5 is the dielectric constant u03b5 0 is the permittivity of free space u03b5 0 8 85 u00d7 10 u2212 12 f m and a e is the effective charging area according to eq 1 variations in the effective charging area the applied voltage and the distance between the electrodes will affect the magnitude of the electrostatic force between the electrodes clearly an increase in the electrostatic area a e will provide a linear increase in force f e and in most applications the valve plate is designed with an area that is significantly larger than the area of the valve opening with typical lateral dimensions in the range of a few millimeters in order for the valve to remain within micro dimensions however the effective charging area that can be incorporated into the valve is still very limited hence the overall electrostatic actuating force that can be generated between the electrodes in the microvalve is also limited increasing the.