| 摘要 |
PURPOSE:To enable reference point and span to be accurately corrected with simple operation and yet make the constitution relatively simple and inexpensive by using two kinds of standard solutions of known ion concentrations. CONSTITUTION:An ion electrode 11 and a reference electrode 12 are dippled in liquid 13 and the voltage being generated is amplified with an amplifier 14 and is converted to digital quantity with an A-D converter 15. First, two kinds of standard solutions of known concentrations are used and the concentration a1, a2 thereof are preset in preset counters 18, 19 respectively. The potentials E1, E2 generated from the standard solutions are expressed by formulas I, II and are stored in a memory 23 by closing a switch 20 thereby energizing a relay 21 and closing relay contacts 22. Next, when a switch 24 is closed to energize control part 25, then a constant C is calculated in an arithmetic part 16. Next, the potential Ex by the specimen solution is supplied to the arithmetic part 16, which in turn closes a switch 26 to energize the control part 27, whereby the concentration (ax) of the specimen solution is displayed in a display device 17 from the operation according to formulaIII. |
