Discussion Forum

For an experiment I am measurering the impedance of a piece of conductive rubber with a 4-point measurement (see the schematic image and picture of the set-up). I am trying to simulate this in COMSOL as well (to see what the stray fields are, since they affect the measured capacitance). How can the capacitance between the two inner electrodes be determined if the outer electrodes supply a voltage. The outer electrodes are set to 0V and 10mV respectively while the inner electrodes are used to measure the impedance. Since I am trying to determine the resistivity and permittivity of the sample, I only need to measure/simulate the resistance and capacitance (hence a DC simulation can be used). For now I used the electrostatics module and made the inner electrodes the terminals. In that way I can determine a capacitance, however in this way it represents a 2-point measurement and not the actual set-up (I expect this to yield different fringe fields at the outer ends of the sample). So is there a way to simulate a 4-point measurement (in COMSOL 4.3)?

Thanks for your suggestions beforehand! (I do not seem to be able to get a MPH file smaller than 5-MB for uploading)