This document discusses various methods of pressure measurement. It describes absolute pressure, gauge pressure, and differential pressure. It then covers several common pressure sensors: diaphragm sensors which use strain gauges or capacitive elements to measure displacement; capacitive pressure sensors; fiber-optic pressure sensors; bellows sensors; Bourdon tube sensors; and manometers including U-tube, well, and inclined styles. Each sensor type is explained along with its typical measurement range and accuracy.