When talking torque transducer, ‘analogue’ or ‘digital’ become barely necessary, being simply a matter 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 according to the physical property they use (including piezoelectric, photovoltaic, etc.) or in accordance with the function they perform (such as measurement of length, temperature, etc.). In the former case one can present a reasonably integrated look at the sensing process, but it is a bit disconcerting when one desires to compare the merits of, say, two kinds of temperature sensors, if one must examine separate sections on resistive, thermoelectric and semiconductor devices to help make the comparison.
Alternatively, to try and differentiate devices by function often is commonly a relatively boring catalogue of numerous unrelated devices. What is important about them is signals are transformed from one form to another. It is also possible to discuss miniature load cell from your functional viewpoint, under headings like length, temperature, etc., appropriate for somebody that actually would like to select or make use of a sensor for the application as opposed to just read round the subject.
The phrase ‘sensors’ and ‘transducers’ are generally popular in the description of measurement systems. The first kind is popular in the USA whereas the latter is more often found in Europe. The option of words in science is pretty important. Recently there has been a propensity to coin new words or to misuse (or misspell) existing words, and this might lead to considerable ambiguity and misunderstanding, and has a tendency to diminish the preciseness from the language. The matter has become very apparent within the computer and microprocessor areas, where preciseness is particularly important, and may seriously confuse persons entering the subject.
The phrase ‘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 big change in a physical stimulus and turns it right into a signal which is often measured or recorded’; a corresponding definition of ‘transducer’ is ‘a device that transfers power from a single system to a different in the same or perhaps in different form’.
A smart distinction is by using ‘sensor’ for that sensing element itself, and ‘transducer’ for the sensing element plus any associated circuitry. For example, thermistors are sensors, given that they reply to a stimulus (changes its resistance with temperature), but only become transducers when connected in a bridge circuit to convert change in potential to deal with improvement in voltage, considering that the complete circuit then transduces from your thermal for the electrical domain. A solar cell is both a sensor and a transducer, because it responds to a stimulus (creates a current or voltage in reaction to radiation) as well as transducer from the radiant for 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 many (though not every) sensors are also transducers.
The distinction is rather small, and once one actually works with a sensor (by using capacity to it) it becomes load cell. An appealing classification of devices may be accomplished by taking into consideration the many forms of energy or signal transfer.
The phrase ‘actuate’ means ‘to put into, or incite to, action’ and actuators are devices that make the display or observable output in a measurement system such as a light-emitting diode (LED) or moving coil meter. These are needless to say transducers employed for output purposes, since they transduce in one domain to another (ie. electrical to radiant for LEDs).