Resistive pressure measurement (ceramic thick-film and metal thin-film technology)
In ceramic thick-film and metal thin-film technology, four resistors are interconnected to create a Wheatstone bridge. During pressurization, the resistors are exposed to the highest strain in the diaphragm center while the strongest compression is found in the edge areas. In ceramic and thin-film cells, the measuring membrane acts at the same time as media separating membrane. No internal transmission fluid is required.
Piezo-resistive pressure measurement (silicon semiconductors)
In semiconductor materials, the change in the specific resistance and thus of the signal results from the variable mobility of the electrons in the crystalline structure. This mobility reacts on mechanical load. The sensitive silicon chip and the process medium are separated by a stainless steel membrane (encapsulation). Depending on the application, paraffin or silicone oil is used as transmission fluid for internal pressure transmission.