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 based on the physical property they normally use (like piezoelectric, photovoltaic, etc.) or in accordance with the function they perform (including measurement of length, temperature, etc.). In the former case anybody can present a reasonably integrated look at the sensing process, however it is just a little disconcerting when one desires to compare the merits of, say, two kinds of Multi Axis Force Sensor, if one must look over separate sections on resistive, thermoelectric and semiconductor devices to create the comparison.
Alternatively, to try and differentiate devices by function often is commonly a rather boring catalogue of numerous unrelated devices. The important thing about the subject is signals are transformed in one form to another. It is also easy to discuss Rotary Torque Sensor through the functional viewpoint, under headings including length, temperature, etc., ideal for someone who actually wants to select or make use of a sensor for the application as opposed to just read across the subject.
The words ‘sensors’ and ‘transducers’ are generally commonly used in the description of measurement systems. The previous is popular in the USA whereas the second is more often utilized in Europe. Deciding on a words in science is pretty important. Lately there has been a tendency 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 from the language. The challenge has been very apparent inside the computer and microprocessor areas, where preciseness is especially important, and can seriously confuse persons entering the niche.
The word ‘sensor’ comes from sentire, meaning ‘to perceive’ and ‘transducer’ originates 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 definition of ‘transducer’ is ‘a device that transfers power from one system to another one within the same or perhaps in different form’.
An intelligent 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, given that they respond to a stimulus (changes its resistance with temperature), but only become transducers when connected in a bridge circuit to transform change in resistance to improvement in voltage, considering that the complete circuit then transduces through the thermal to the electrical domain. A solar cell is both a sensor along with a transducer, because it responds to a stimulus (creates a current or voltage in reaction to radiation) as well as transducer from the radiant to the electrical domain. It will not require any associated circuitry, though in reality an amplifier would usually be used. All transducers thus have a sensor, and lots of (though its not all) sensors are also transducers.
The distinction is pretty small and as soon as one actually uses a sensor (by applying capability to it) it will become Jr S Beam Load Cell. A fascinating classification of devices can be achieved by taking into consideration the various hdjjdy of energy or signal transfer.
The term ‘actuate’ means ‘to put in, or incite to, action’ and actuators are devices that produce the display or observable output in a measurement system like a light-emitting diode (LED) or moving coil meter. These are needless to say transducers used for output purposes, because they transduce from one domain to another one (ie. electrical to radiant for LEDs).