Andre

That is the correct formula.

Another way is to determine the current you want and calculate values from
this.

ie. Let Vs = 14V, Let i = 1mA, Let Vref = 2.57

R2 = Vref/i = 2.57/1mA = 2570
R1 = (Vs - Vref)/1mA = 11430

(use closest values R1 = 12k, R2 = 2k7 , Vref' = 2.571

Regards

David Huisman

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.