When talking torque transducer, ‘analogue’ or ‘digital’ become barely important, being just a matter of approach to operation, and that it must be the underlying physical principles which can be all-important.
Classification of sensors
In discussing sensing devices one has to decide whether to classify them based on the physical property they normally use (including piezoelectric, photovoltaic, etc.) or based on 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, but it is a little disconcerting when one wishes to compare the merits of, say, two kinds of temperature sensors, if one must examine separate sections on resistive, thermoelectric and semiconductor devices to make the comparison.
Alternatively, to try to differentiate devices by function often is usually a rather boring catalogue of numerous unrelated devices. The important thing on them is signals are transformed from one form to another. It is also easy to discuss compression load cell from the functional viewpoint, under headings like length, temperature, etc., appropriate for somebody who actually would like to select or use a sensor for a particular application rather than just read round the subject.
The words ‘sensors’ and ‘transducers’ are generally widely used within the description of measurement systems. The previous is popular in the united states whereas the second is a lot more often found in Europe. Deciding on a words in science is quite important. Lately there has been a propensity to coin new words or even to misuse (or misspell) existing words, and this can lead to considerable ambiguity and misunderstanding, and tends to diminish the preciseness in the language. The matter continues to be very apparent in the computer and microprocessor areas, where preciseness is particularly important, and may seriously confuse persons entering the topic.
The phrase ‘sensor’ hails from sentire, meaning ‘to perceive’ and ‘transducer’ originates from transducere meaning ‘to lead across’. A dictionary definition Chambers 20th Century) of ‘sensor’ is ‘a device that detects a big change in a physical stimulus and turns it into a signal which may be measured or recorded’; a corresponding concept of ‘transducer’ is ‘a device that transfers power in one system to a different in the same or in different form’.
A sensible distinction is to apply ‘sensor’ for that sensing element itself, and ‘transducer’ for the sensing element plus any associated circuitry. As an example, thermistors are sensors, given that they respond to a stimulus (changes its resistance with temperature), only become transducers when connected in a bridge circuit to convert alternation in resistance to alternation in voltage, because the complete circuit then transduces from your thermal to the electrical domain. A solar cell is both a sensor along with a transducer, because it responds to your stimulus (produces a current or voltage in reaction to radiation) and in addition transducer from the radiant towards the electrical domain. It does not require any associated circuitry, though in practice an amplifier would usually be applied. All transducers thus hkjrzk a sensor, and lots of (though its not all) sensors are also transducers.
The distinction is pretty small, and once one actually works with a sensor (by making use of capability to it) it becomes weight sensor. A fascinating classification of devices can be achieved by taking into consideration the various forms of energy or signal transfer.
The word ‘actuate’ means ‘to put into, or incite to, action’ and actuators are devices that make the display or observable output in a measurement system like a light-emitting diode (LED) or moving coil meter. They are of course transducers used for output purposes, because they transduce from one domain to a different (ie. electrical to radiant for LEDs).