When talking aerospace sensors, ‘analogue’ or ‘digital’ become hardly necessary, being simply a matter of approach to operation, and that it is the underlying physical principles that are all-important.
Classification of sensors. In discussing sensing devices one must decide whether or not to classify them according to the physical property they normally use (like piezoelectric, photovoltaic, etc.) or according to the function they perform (such as measurement of length, temperature, etc.). Within the former case you can present a reasonably integrated take a look at the sensing process, but it is just a little disconcerting when one desires to compare the merits of, say, two types of Multi Axis Force Sensor, if one must look over separate sections on resistive, thermoelectric and semiconductor devices to help make the comparison.
Alternatively, to try to differentiate devices by function often is commonly an extremely boring catalogue of numerous unrelated devices. The important thing about them is signals are transformed in one form to another. It is additionally possible to discuss Torque Sensor from the functional viewpoint, under headings such as length, temperature, etc., appropriate for someone who actually wants to select or make use of a sensor for the application rather than just read across the subject.
The words ‘sensors’ and ‘transducers’ are generally widely used inside the description of measurement systems. The first kind is popular in the us whereas the latter is a lot more often used in Europe. The choice of words in science is quite important. Lately we have seen a propensity to coin new words or misuse (or misspell) existing words, and this may lead to considerable ambiguity and misunderstanding, and tends to diminish the preciseness of the language. The matter has been very apparent inside the computer and microprocessor areas, where preciseness is particularly important, and can seriously confuse persons entering the niche.
The phrase ‘sensor’ comes from sentire, meaning ‘to perceive’ and ‘transducer’ is from transducere meaning ‘to lead across’. A dictionary definition Chambers Twentieth Century of ‘sensor’ is ‘a device that detects a change in a physical stimulus and turns it right into a signal which can be measured or recorded’; a corresponding meaning of ‘transducer’ is ‘a device that transfers power from a single system to another in the same or perhaps in different form’.
A sensible distinction is to use ‘sensor’ for your sensing element itself, and ‘transducer’ for your sensing element plus any associated circuitry. For example, thermistors are sensors, because they respond to a stimulus (changes its resistance with temperature), but only become transducers when connected in a bridge circuit to transform change in effectiveness against alternation in voltage, since the complete circuit then transduces from the thermal towards the electrical domain. A solar cell is both a sensor and a transducer, since it responds to your stimulus (generates a current or voltage in response to radiation) and also transducer from the radiant towards the electrical domain. It will not require any associated circuitry, though in reality an amplifier would usually be utilized. All transducers thus have a sensor, and several (though its not all) sensors will also be transducers.
The distinction is rather small and the moment one actually utilizes a sensor (by making use of power to it) it might be Miniature Force Sensor. An appealing classification of devices can be accomplished by thinking about the various hdjjdy of energy or signal transfer.
The phrase ‘actuate’ means ‘to placed into, or incite to, action’ and actuators are devices that produce the display or observable output in a measurement system for instance a light-emitting diode (LED) or moving coil meter. They are of course transducers employed for output purposes, because they transduce from one domain to another one (ie. electrical to radiant for LEDs).