Patent ID: 7372277
Filing Date: 2008-05-13
Classification: G01N

Abstract:
1. A method for use with a digitally controlled power supply and a reaction cell having first and second load electrodes and a liquid sample disposed between the load electrodes, the power supply coupled with the first load electrode to provide an excitation voltage to said first load electrode, a first signal line coupling the first load electrode with a first analog-to-digital converter, and a voltage sensor coupled with the second load electrode, the voltage sensor having a second signal line coupled to a second analog-to-digital converter, the method comprising the steps which follow in the order given: making a first approximation to a digital control signal for the power supply; measuring a first potential at the second load electrode by means of the second signal line; making a second approximation to the digital control signal for the power supply, wherein the second approximation differs from the first approximation based on the difference between the first potential measured at the second load electrode and a target value; measuring a second potential at the second load electrode by means of the second signal line; making a third approximation to the digital control signal to the power supply, wherein the third approximation differs from the second approximation based on the difference between the second potential measured at the second load electrode and the target value and measuring a measurement potential at the first load electrode by means of the first signal line, said measurement potential being used for analysis of the liquid sample.