Question

For a resistivity cell, it's said that a temperature and pressure sensor were not placed within the cell because of the high voltage applied and the partial capacitance generated by the sensor. How would a high voltage affect such a sensor and what does it mean by "partial capacitance generated by the sensor"?

Answer 1

it is quite obvious that, in a resistivity cell a high voltage developed may lead to discharge of the gas present inside of it which creates a partially conducting medium. Taking this into account, the material of a temperature sensor/pressure sensor might have probability to get melt/fused and will distroy the material. also there is a high probability that non-conducting material may get polarized due to the high field which creates a capacitance which will last as long as field/voltage is present. This additional capacitance will produce a noise in the signal.

Most of the pressure sensors are made from a piezoelectric material which are non conducting in nature. thus they may get partially polarized and form a temporary capacitance which will last with the applied voltage