Vacuum degree definition
The degree of vacuum refers to the degree of gas thinness under vacuum. If the pressure in the device under test is lower than atmospheric pressure, the pressure measurement requires a vacuum gauge. The value read from the vacuum gauge is called the degree of vacuum. The vacuum value is a value indicating that the actual value of the system pressure is lower than the atmospheric pressure, that is, the vacuum degree = atmospheric pressure - absolute pressure, absolute pressure = atmospheric pressure + gauge pressure (-vacuum degree).