Pressure is commonly measured by monitoring the movement of a
diaphragm which is distended by a build up of pressure (or of vacuum). One
way of monitoring diaphragm movement is to measure a change in
capacitance of a system coupled to the diaphragm. In this case two concentric
cylinders form a capacitance with the central cylinder coupled to the
diaphragm.
This experiment illustrates the use of a variable capacitance fixed to a flexible
membrane in pressure sensing.