Every pressure gauge serves essentially the same purpose: to convert a reading of pressure in an enclosed system into a signal that can be read by humans or a control system. The differences between pressure switches are found in other areas. They are distinguished from each other based on their size, shape, configuration, what kinds of pressurized materials they are used to measure, their composition, their cost, their reading type (metric or non-metric) and many other determining factors that are more closely related to issues of specific application than issues of concept. One of the defining characteristics of a pressure gauge is whether its readout is analogue or digital.
Analogue and digital readouts both have their advantages. The primary advantages of analogue pressure gauges is that they can be more expensive than digital readouts and that they often don’t need to be connected to a power source. Since there is no electronic display on an analogue pressure gauge, there is no need to connect it to a power source. This can be tremendously advantageous in areas where access to electricity is not guaranteed, such as on remote pipeline systems.
Digital pressure switches, on the other hand, offer a distinct set of advantages as well. They generally can be read more quickly and easily by technicians. This means that people reading the gauges can quickly take note of their readings and quickly make decisions or take quick notes based on them. This can be particularly important during emergencies. Also, because they read out precise, numerical values, they often can be read more accurately than analogue gauges, which sometimes can be ambiguous in their displays.
Digital pressure gauges and analogue pressure gauges both have their advantages and disadvantages – each variety is appropriate under different circumstances.