Pressure transducers are electromechanical devices that convert pressures to electrical signals which can be recorded with a data system such as that used for recording strain gage signals. Several typical pressure transducers used in wind tunnel operation are shown in Fig. 6-9. The internal cavity of the transducer is divided into two parts by a thin metal diaphragm. The pressure to be measured is applied to one side of the diaphragm and a reference pressure is applied to the other side. The resulting differential pressure causes a bending of the thin metal diaphragm. The displacement of the diaphragm is sensed electrically, Common techniques are to let the movement of the diaphragm cause changes in tension of very fine resistance wires which are actually strain gages, or to use the movement of the diaphragm to change the inductance or capacitance of an electrical circuit. Transducers can be bought commercially for measuring any pressure in the range normally required in wind tunnels except the very low pressures found in high Mach number tunnels. Design pressure ranges of 0 to 0.3 to 0 to 5000 psi (absolute or gage) are readily available and cost from about 200 dollars up, with the lower-range transducers costing more. They are generally precision instruments and often yield signals that are consistent to 0.1 per cent of design pressure or better when used properly.

压力传感器是一种将压力信号转换成电信号的电动机械装置。电信号可应用像用来记录应变仪信号那样的数据系统来记录。风洞中常用的几种不同类型的压力传感器示于图6-9（此略）。传感器的内腔由一块金属薄膜分隔成两部分。把待测压力接到薄膜的一侧，参考压力接到另一侧，由此而产生的压差引起金属薄膜弯曲。薄膜产生的位移通过电学方法来检测。通常的做法是让薄膜的运动引起极细电阻丝(实际上是应变仪)伸缩，或是利用薄膜的运动来改变某一电路中的电感或电容。市场上可以买到测量风洞中通常所需量程内任意压力的传感器，但买不到测量高马赫数风洞中极低压力的传感器。设计压力范围从0～0.3磅/英寸²直到0~5000磅/英寸²（绝对压力或表压)的压力传感器很容易买到，其价格从200美元起码，低压范围内的传感器价格要昂贵些。压力传感器一般都是精密仪器，如果使用得当可以得到相当于设计压力千分之一或更高的准确度。

Pressure transducers have the following advantages over manometers and other pressure gages: they provide a signal proportional to pressure which can be automatically recorded by the usual wind tunnel data system, they are relatively low volume devices and consequently respond more rapidly to pressure changes, and they are small enough to be mounted inside some wind tunnel models. Their major disadvantages relative to a good manometer is that they must be calibrated whereas the manometer with a known fluid can be considered a pressure standard.

压力传感器同压力计和其他压力表比较起来有如下优点。它们给出的信号与压力成正比，这些信号可以用通常的风洞数据系统自动记录；它们是一种容积相当小的装置，因此，对压力变化的反应也迅速得多；还有，它们体积足够小，能够装到某些风洞模型的内部。压力传感器同好的压力计相比，其主要缺点是必须校准，而使用已知液体的压力计却可以看作是一种压力标准。