Final answer:
A supply pressure gauge is used for monitoring tank pressure, such as in scuba tanks or gas cylinders.
Step-by-step explanation:
A supply pressure gauge is used to measure the pressure of gas within a tank, such as a scuba tank or a medical gas cylinder. These gauges typically read zero at atmospheric pressure, and provide a gauge pressure reading, which is the pressure relative to atmospheric pressure. When the pressure inside the tank is greater than atmospheric pressure, the gauge will indicate a positive value. This allows for the monitoring of tank pressure to ensure there is enough gas for the intended use, be it industrial, medical, or recreational.
Gauges vary in sensitivity and application. For instance, tire pressure gauges are designed specifically for measuring the internal pressure of vehicle tires, while ionization gauges are used in industrial vacuum systems due to their high sensitivity. Propane tank gauges are useful for grilling to monitor how much gas is left in the tank, taking into account that readings can differ depending on the temperature.