a zero applied magnetic field when the sample expands by an infinitesimal amount x due to a change in temperature and or applied magnetic field then the gaps in the capacitors will change to d 1 d x and d 2 d u2212 x in order to keep the balance signal null i e v balance 0 the microprocessor in the circuit will adjust the voltage amplitude ratio across the variable inductors by an amount u03b4u to compensate for the change in gap across each of the two capacitors the voltage across each capacitor will then be u 0 u2212 u03b4u u2208 a d x u 0 u03b4u u2208 a d u2212 x this result shows the important fact that the measurement of the sample expansion is independent of the temperature dependent permittivity u2208 t of the gas medium between the capacitor plates thus greatly reducing the contribution of the gas adsorbed to capacitor 39 s plates of the cell itself to the raw data of the dilatometer fig7 shows an electrical schematic of the dilatometer cell and related detection system in accordance with an embodiment a processor is coupled to a user interface and configured to measure a ratiometric change in capacitance of the dilatometer cell as a result of a corresponding dimensional change of a mounted sample the processor is configured to receive a balance signal and adjust each of the amplitude of the drive signal and the ratio of the transformer signals the dilatometer cell itself is indicated as the portion of the circuit contained within the dashed oval the.