What type of gauge is capable of measuring and displaying both positive and negative pressures?

A compound gauge is specifically designed to measure and display both positive and negative pressures. This capability arises from its construction, which incorporates both a vacuum scale and a pressure scale. The vacuum scale shows negative pressure (below atmospheric pressure), while the pressure scale indicates positive pressure (above atmospheric pressure).

This dual functionality makes compound gauges particularly useful in applications where processes can involve varying pressure states, such as in refrigeration, aerodynamics, or when dealing with vacuum systems.

Other types of gauges, such as manometers, typically measure pressure relative to atmospheric pressure but are primarily used for measuring small pressure differences and may not have a built-in design to display both ranges effectively as a compound gauge does. Digital gauges can measure both positive and negative pressures, but they are not defined by the same characteristics as compound gauges, as they can come in various configurations that don't necessarily include both scales. Standard gauges, on the other hand, generally measure only positive gauges pressure. Thus, the compound gauge is the most accurate answer, as it combines the attributes necessary to handle both positive and negative pressures seamlessly.