In the potentiometric type sensors, a multi-finger metal brush / rake is in contact with a resistive strip, while the butterfly valve is turned from the lower mechanical stop ( minimum air position ) to WOT, there is a change in the resistance and this change in resistance is given as the input to the ECU.
32.
The amount of apparent amylose can be determined either by measuring the absorbency of the starch-iodine complex ( blue-value ) and relating this value to that of pure amylose and amylopectin standards or by measuring the amount of iodine ( mg ) bound per 100 mg of starch in a potentiometric titration and relating the value to the amount bound by an amylose standard.
33.
Non-ideal behaviour can result from measurement errors ( " e . g . " a poorly calibrated electrode, an insufficient equilibration time before recording the electrode reading, drifts in ionic strength ), sampling errors ( " e . g . " low data densities in the linear regions ) or an incomplete chemical model ( " e . g . " the presence of titratable impurities such as carbonate in the base, or incomplete precipitation in potentiometric titrations of dilute solutions, for which Gran " et al . " ( 1981 ) propose alternate approaches ).
