When talking torque transducer, ‘analogue’ or ‘digital’ become barely necessary, being just a case of approach to operation, and that it must be the underlying physical principles that are 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 (such as piezoelectric, photovoltaic, etc.) or in accordance with the function they perform (such as measurement of length, temperature, etc.). Within the former case anybody can present a reasonably integrated look at the sensing process, but it is just a little disconcerting when one desires to compare the merits of, say, 2 kinds of temperature sensors, if one has to examine separate sections on resistive, thermoelectric and semiconductor devices to make the comparison.
Alternatively, to try and differentiate devices by function often is usually an extremely boring catalogue of numerous unrelated devices. The main thing on them is signals are transformed in one form to a different. It is also easy to discuss compression load cell from your functional viewpoint, under headings such as length, temperature, etc., suitable for somebody that 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’ both are widely used inside the description of measurement systems. The previous is popular in the united states whereas the latter is much 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 to misuse (or misspell) existing words, and this can lead to considerable ambiguity and misunderstanding, and has a tendency to diminish the preciseness from the language. The issue has become very apparent inside the computer and microprocessor areas, where preciseness is particularly important, and may seriously confuse persons entering the niche.
The term ‘sensor’ comes from sentire, meaning ‘to perceive’ and ‘transducer’ is 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 from a single system to another one within the same or perhaps in different form’.
A sensible distinction is to apply ‘sensor’ for the sensing element itself, and ‘transducer’ for that sensing element plus any associated circuitry. As an example, thermistors are sensors, because they react to a stimulus (changes its resistance with temperature), only become transducers when connected in a bridge circuit to transform improvement in effectiveness against improvement in voltage, because the complete circuit then transduces from the thermal for the electrical domain. A solar cell is both a sensor and a transducer, because it responds to some stimulus (produces a current or voltage responding to radiation) and in addition transducer from the radiant for the electrical domain. It does not require any associated circuitry, though in practice an amplifier would usually be utilized. All transducers thus hkjrzk a sensor, and lots of (though not all) sensors are also transducers.
The distinction is quite small and as soon as one actually utilizes a sensor (by applying capacity to it) it becomes load sensor. An appealing classification of devices may be accomplished by thinking about the many forms 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. They may be of course transducers used for output purposes, since they transduce from one domain to another (ie. electrical to radiant for LEDs).