A pH SENSOR WITH INTERNAL SOLUTION GROUND

摘要

The invention relates to an internal solution ground (502) for primary use with a pH sensor (500, 482), especially with a multi-sensing instrument (700, 900, 280, 480) monitoring a pH sensor (500, 482) and one or more additional secondary sensors (702, 484, 486, 488) having non-isolated circuits (710, 712, 481, 483, 485, 487). In one aspect, a pH sensor assembly (500) includes a pH electrode (108), a reference electrode, and an internal solution (ground wire (502). The internal solution ground wire (502) shares a liquid junction (122) with the reference electrode (108) but is protected by the reference fill solution (118). The internal solution ground (502) can be electrically isolated through a capacitor (902, 471, 473, 475) or, alternately, a capacitor (902, 471, 473, 475) and resistor (903) in parallel.