PRINCIPLES OF NAVAL ENGINEERING 



Because there will always be some error of 

 measurement, and because the error may actu- 

 ally be considerably greater than that indicated 

 by the percentage of guaranteed accuracy, the 

 calibration of any measuring device requires 

 the highest possible precision. 



Instrument sensitivity is sometimes confused 

 with instrument accuracy. This is a big mistake. 

 The sensitivity of an instrument refers to the 

 ability of the instrument to respond to changes 

 in the value of the measured variable. K an 

 instrument can respond to very small changes 



in the measured variable, it is a very sensitive 

 instrument; if larger changes in the measured 

 variable are required to produce effective motion 

 of the measuring element, the instrument is less 

 sensitive. 



Sensitivity is quite directly related to fric- 

 tion within an instrument. An instrument that 

 has relatively small energy losses because of 

 friction will, all other things being equal, be 

 more sensitive than an instrument with rela- 

 tively large friction losses. 



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