1 r 40 r 10 u2062 1 r 20 r 30 u2062 1 1 b a u2062 t 0 u2062 r 40 r 10 u2062 1 r 20 r 30 u2062 u03b4 u2062 u2062 t t 0 u2062 b a u2062 t 0 u2062 r 40 r 10 u2062 1 r 20 r 30 u2062 u03b4 u2062 u2062 t t 0 2 u2062 ln u2061 nr 2 r 1 u2062 11 by substituting the previously calculated equation 4 into the equation 11 the following equation 12 can be achieved v ref u2061 t v d u2062 u2062 1 u2061 t 0 r 20 r 30 u2062 kt 0 q u2062 1 r 40 r 10 u2062 1 r 20 r 30 u2062 u2062 ln u2062 u2062 nr 2 r 1 r 20 r 30 u2062 kt 0 q u2062 1 1 b a u2062 t 0 u2062 r 40 r 10 u2062 1 r 20 r 30 u2062 ln u2062 u2062 nr 2 r 1 v bg u2062 v d u2062 u2062 1 u2061 t 0 u03b7 1 u2062 kt 0 q u2062 u03b4 u2062 u2062 t t 0 r 20 r 30 u2062 kt 0 q u2062 b a u2062 t 0 u2061 b a u2062 t 0 u2062 r 40 r 10 u2062 1 r 20 r 30 u2062 ln u2062 u2062 nr 2 r 1 u03b7 1 u2062 kt 0 q u2062 u03b4 u2062 u2062 t t 0 2 12 as shown in the equation 12 it is found that by adding the fourth fixed resistor r 4 the resistance characteristic of the fourth fixed resistor r 4 that is the resistance value r 40 at the reference temperature to of the fourth.