AutoQuiz: What Reading Do You Get From a Disconnected Pressure Gauge?

AutoQuiz is edited by Joel Don, ISA's social media community manager.

This automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for more information about the CCST program.

What pressure, in pounds per square inch (psi), would be indicated by an absolute pressure gauge that is lying on a workbench not connected to anything?

a) 0
b) 29
c) 14.7
d) 2.9
e) none of the above

Atmospheric pressure (P_atmospheric), absolute pressure (P_absolute), and gauge pressure (P_gauge) have the following mathematical relationship.

P_absolute = P_gauge + P_atmospheric

Atmospheric pressure is 14.7 psi.

The correct answer is C.

About the Editor
Joel Don is the community manager for ISA and is an independent content marketing, social media and public relations consultant. Prior to his work in marketing and PR, Joel served as an editor for regional newspapers and national magazines throughout the U.S. He earned a master's degree from the Medill School at Northwestern University with a focus on science, engineering and biomedical marketing communications, and a bachelor of science degree from UC San Diego.

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