Besides the traditional vacuum gauges with mechanical sensors (e.g., Bourdon, capsule gauge) diaphragm manometers with electronical diaphragm sensors are well established (Piezo and capacitance gauges). The pressure to be measured is separated by a diaphragm from a reference vacuum and compared to the latter. The movement of the diaphragm is registered either by a piezo resistive system or the diaphragm is part of a capacitor (capacitance vacuum system). For improved chemical resistance the diaphragm is often made of an aluminium oxide ceramic. The pressure measurement is independent of the type of gas.