There are several names to describe a Pressure Sensor. In general a Pressure Transducer has a mV output, Pressure Transmitter has an amplified output but don’t forget there are Pressure gauges which give a visual indication of the measured pressure, or even pressure switches which can be set to trigger at a given pressure level. Other terminology extends to pressure capsules, pressure sensing elements, packaged pressure sensors, digital output pressure sensors for example.
There are many types or variants of pressure sensor depending mainly on the application where the sensor will be used. These are electro-mechanical devices and in general are fitted directly to the medium being measured. There are many considerations such as temperature, size of the pressure sensor, corrosive environment, ingress protection, signal output required, material of construction, cost.
Pressure sensors start with the sensitive element that will convert the pressure of a gas or liquid into an electrical signal. The easiest way to understand this principle is to consider them as strain gauges. There are many technologies of pressure sensing elements, each has a unique feature which offers a better solution for the application. Piezo resistive technology example is great for volume applications, gas measurement, barometrics however for liquids there are some compromises to be made. For liquids, it is very common to have a diaphragm to isolate the pressure sensing element which in itself presents challenges with diaphragm materials, sensing technology, size, accuracy etc.
There are several outputs available for Pressure Sensors. The most common by far is an Amplified output (referred to as analogue output) such as 4-20mA, 0-5 V, 0-10 VDC for example. Digital outputs such as SDI, I2C, RS-485 or RS-232 are available as an option on most Pressure sensor families however reduce the Frequency response, but would increase the user flexibility and accuracy of the sensor. On some Pressure sensors, mV output is available which delivers an excellent Frequency response but may need some signal conditioning.