Category: General Concepts.

Inertial Navigation

The original meaning of the word navigation is “ship driving.” In ancient times when sailing boats were used, navigation was…

Concerning Techniques Mentioned Above Concerning capacitive sensors, the NASA Langley Research Center is developing sensors based on patterns of conductors…

Pneumatic Gaging

Pneumatic gages have pressurized air exiting gage orifices. The air velocity differential or backpressure is a function of the separation…

Descriptions of the Relatively Mature Measuring Techniques

The following descriptions will also refer to some of the relevant vendors, whose addresses are found in Table 7.2. Additional…

Optical Encoder Displacement Sensors

The detection of angular and linear motion is a key function in a multitude of systems such as machine tools,…

Two-Frequency Heterodyne Interferometer

Figure 6.50 shows the commercially available two-frequency Michelson interferometer operating with a Zeeman-stabilized He–Ne laser source. This laser emits two…

Refractive Index of Air

The length scale of a displacement interferometer that is operated in ambient air is given by λA = λV/nA, where…

Frequency Stabilization of He–Ne Lasers

The resonant frequency (and the wavelength λ) of the laser is determined in part by the distance between the two…

Laser Interferometer Displacement Sensors

In the past few years, very high precision, numerically controlled machine tools have been developed. To achieve the potential precision…

Piezoelectric Transducers and Sensors

Piezoelectricity, discovered in Rochelle salt in 1880 by Jacques and Pierre Curie, is the term used to describe the ability…

Capacitive Sensors—Displacement

Capacitive sensors are extensively used in industrial and scientific applications. They are based on changes in capacitance in response to…

Linear-Variable Inductor

There is a little distinction between variable-reluctance and variable-inductance transducers. Mathematically, the principles of linear-variable inductors are very similar to…