Explanatory notes
… in the quantity to be measured (e.g., Bourdon tube, diaphragm, bellows, semiconductors) moving a needle or a … : (i) a primary device (e.g., Pitot or Venturi tube, simple diaphragm, orifice plates, shaped nozzle) to set up a … pressure, and (ii) a differential pressure gauge (float, diaphragm, differential pressure, oscillating ring balance …