Patent ID: 6936146

Claim:
A readout meter using an electrochemical biosensor test strip provided with an insulating substrate, a reference electrode and a working electrode formed parallel in a lengthwise direction on the insulating substrate, and a reagent which is fixed over the reference electrode and the working electrode on the insulating substrate, and which generates electric charges corresponding to the concentration of a specific material to be analyzed by reacting to this material depending on the insertion of sample into the test strip and the readout meter, comprising: a working voltage generating circuit applying a working voltage to the working electrode; a voltage converting device converting the electric current flowing through the working electrode into voltage; an amplifier device outputting an analogue voltage signal, amplifying the converted voltage from the voltage converting device; wherein the voltage converting device and amplifier device are provided as separate elements and the voltage converting device includes an operational amplifier; an A/D converter converting the analogue voltage signal from the amplifier into a digital voltage signal; and a controller which operates the working voltage generating circuit to apply a first voltage to the working electrode when the test strip is inserted into the readout meter (tO), to apply a second voltage to the working electrode for a fixed period of time after a certain time (t 2 ) when the sample is inserted (t 1 ), then (t 3 ) operates the working voltage generating circuit to apply a third voltage to the working electrode, and measures the concentration of the material to be analyzed by reading the digital voltage signal from the A/D converter after a certain time (t 4 ) from the applying point of the third voltage (t 3 ); wherein the voltage converting device is set to convert the peak in the current generated at the applying point of the third voltage (t 3 ) into a corresponding voltage without distortion, and the amplifier device is set to make the digital voltage signal at the measuring time (t 4 ) become below the reference voltage of an A/D converter.