When talking torque sensor, ‘analogue’ or ‘digital’ become hardly required, 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 must decide whether to classify them according to the physical property they utilize (including piezoelectric, photovoltaic, etc.) or according to the function they perform (like measurement of length, temperature, etc.). Inside the former case you can present a reasonably integrated view of the sensing process, yet it is just a little disconcerting when one desires to compare the merits of, say, two types of temperature sensors, if one must look through separate sections on resistive, thermoelectric and semiconductor devices to create the comparison.
Alternatively, to try to differentiate devices by function often is commonly an extremely boring catalogue of numerous unrelated devices. What is important on them is signals are transformed from one form to a different. Additionally it is easy to discuss button load cell from your functional viewpoint, under headings such as length, temperature, etc., appropriate for somebody who actually wants to select or make use of a sensor for the application rather than just read around the subject.
The text ‘sensors’ and ‘transducers’ are generally popular within the description of measurement systems. The first kind is popular in the USA whereas the latter is a lot more often found in Europe. The option of words in science is quite important. Lately we have seen a propensity to coin new words or even to misuse (or misspell) existing words, and this might lead to considerable ambiguity and misunderstanding, and is likely to diminish the preciseness in the language. The challenge continues to be very apparent in the computer and microprocessor areas, where preciseness is especially important, and will seriously confuse persons entering the subject.
The word ‘sensor’ is derived from sentire, meaning ‘to perceive’ and ‘transducer’ comes from transducere meaning ‘to lead across’. A dictionary definition Chambers 20th Century) of ‘sensor’ is ‘a device that detects a big difference in a physical stimulus and turns it in to a signal which can be measured or recorded’; a corresponding meaning of ‘transducer’ is ‘a device that transfers power in one system to another inside the same or perhaps in different form’.
A sensible distinction is to use ‘sensor’ for your sensing element itself, and ‘transducer’ for that sensing element plus any associated circuitry. For instance, thermistors are sensors, because they react 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, considering that the complete circuit then transduces through the thermal for the electrical domain. A solar cell is both a sensor and a transducer, since it responds to some stimulus (creates a current or voltage in reaction to radiation) and in addition transducer through the radiant towards the electrical domain. It can not require any associated circuitry, though in reality an amplifier would usually be utilized. All transducers thus hkjrzk a sensor, and several (though not every) sensors can also be transducers.
The distinction is pretty small, and as soon as one actually uses a sensor (by using capacity to it) it becomes weight sensor. A fascinating classification of devices can be accomplished by thinking about the many forms of energy or signal transfer.
The phrase ‘actuate’ means ‘to placed 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 needless to say transducers employed for output purposes, because they transduce from one domain to another (ie. electrical to radiant for LEDs).