I am working with a 500 MΩ resistor, assembled in the fiberglass tube with both ends closed. There is dielectric-silicon filled in between the resistor and fiberglass tube, which gets cured in 24 hours.
When I measure the resistance of the resistor itself, it's showing 500 MΩ. However after assembly into the fiberglass tube, it was showing in 450 MΩ range. Then after cutting the top half of fiberglass tube (horizontally cutting) the resistor was again showing 500 MΩ.
I think the silicon expands during the curing process and it puts pressure on the resistor to make it read low resistance. Can this happen? What would be the impact of pressure on resistor and what is the easy and best way to measure the impact?