The low natural frequency of the pressure gages described so far has limited their use to essentially steady pressures. Although the pressures to be measured in many experiments are substantially steady, there are cases, as in the study of turbulent or separated flows, of flutter or in tests carried in a shock tube, where it is essential to measure unsteady pressures.
To meet these requirements pressure transducers that convert a pressure signal into an electrical signal are required. In fact, transducers can do the following:
■ can be built having high resonant frequencies;
■ can be miniaturized and thus can be installed adjacent to or even within the model to be tested, thus reducing the delays due to the transmission of pressure signals in pipes.
Transducers greatly simplify the procedure for getting and recording data since the electrical signal from the transducer can be digitized and sent to a computer. This characteristic has led in time to the adoption of transducers even when pressure is steady, especially when many pressure measurements are needed.