Typically an instrument used to take a simple measurement, eg, a dc ammeter, is calibrated against a standard traceable to the National Bureau of Standards. The value may then be specified with some degree of confidence: “30 amps dc.” An ac or pulsating measurement gets to be a little trickier, as you engineering types are aware, because we then have to account for duty cycle, rms v average v effective v peak, phase angle, etc etc. Yet even in these cases we can usually declare with some assurance, “4000 Amps AC RMS effective continuous”

However, some values are not so easily specified, especially when the instrument or the standard it is calibrated against are subject to a large number of variables, when the instrument used to make the measurement has been calibrated against a standard of uncertain stability, or when the results of it use depend heavily on exactly how the calibration is performed or the measurement made

Bear with me

Back in my school days when I was keeper of a campus “wired wireless” station I was required to show that my field strength didn’t exceed certain FCC guidelines. When a Professor of Electrical Engineering volunteered to take a field-strength measurement, he asked me what that value was, assuring me that such measurements typically are so uncertain that he could get me “any result you want”

To impart a degree of confidence–without having to admit the result is only “approximately” or even worse, “roughly” accurate–the term “calibrated” is sometimes added; eg, “110 calibrated microvolts per meter.” Under these conditions, “calibrated” means uncalibrated

Can anyone supply further examples of this usage--Thanks all

Cleave pops to mind, but then my cleft mind hasn't cleaved to me well lately.

quote:

Under these conditions, “calibrated” means uncalibrated

Not sure what you mean, Dale.

kalleh: Perhaps I expected more response from my fellow engineers, who would be more likely to appreciate it's being a Janus

Often "calibrated" means "...but you have to know something that isn't entirely obvious":


Sometimes you'll see an ad in the paper or mag for a product whose performance parameters are described as "calibrated square inches" or "calibrated feet per second," which leaves you wondering if their instruments were calibrated why do they have to tell you so

We dusted the ornaments.
We dusted for fingerprints.

We screened the results. (Did we show them or censor them?)