Following is a definition of terms frequently used in the instrumentation, industrial automation and test & measurement communities.
g: The force of acceleration due to gravity equal to 32.1739 ft/sec2 or 386 in./sec2.
Gage Factor: A measure of the ratio of the relative change of resistance to the relative change in length of a piezoresistive strain gage.
Gage Length: The distance between two points where the measurement of strain occurs.
Gauge Pressure Transducer: A transducer which measures pressure in relation to the ambient pressure.
Gauge pressure: Absolute pressure minus local atmospheric pressure.
Gain: The amount of amplification used in an electrical circuit.
Galvanometer: An instrument that measures small electrical currents by means of deflecting magnetic coils.
GPH: Volumetric flow rate in gallons per hour.
GPM: Volumetric flow rate in gallons per minute.
Ground: (1) The electrical neutral line having the same potential as the surrounding earth. (2) The negative side of DC power supply. (3) Reference point for an electrical system.
Grounded Junction: A form of construction of a thermocouple probe where the hot or measuring junction is in electrical contact with the sheath material so that the sheath and thermocouple will have the same electrical potential.