Any device that converts an applied pressure into an electrical signal is known as a pressure transducer. The different types of pressure transducer developed include thick film, thin film and semiconductor strain gauge, etc. All these sensing technologies are transducers and provide the electrical signal of a millivolt. This varies when connected to an appropriate power supply and if there is a change in pressure.
Characteristically, the primary sensing element generates a pressure transducers output signal. As it is difficult to attain fixed electrical tolerances during manufacture, it becomes essential to add a circuit and recompense for errors over the temperature range.
It is possible to opt for pressure transducers without other electronics, which are known as pressure capsules or headers, used by instrument manufacturers who use their own micro-electronics for the pressure transducer.
A pressure transmitter, on the other hand, is simply a pressure transducer with extra electronics to send out an output signal. In the past, pressure transmitters were usually found in large processing plants; also the sensors used were relatively expensive and heavier. In recent years, some industries have chosen a pressure transmitter which gives 4-20mA output as it only needs two wire connections. The solid-state electronic technology has reduced in terms of the size and cost of these pressure sensors. It has now become difficult to differentiate between a pressure transducer and transmitter by size and shape.
One of the main benefits of pressure transmitters and pressure transducers with a high voltage output is that they add in zero & span adjustment potentiometers which allow for the pressure sensors to be easily calibrated.
