APPARATUS AND METHOD OF DETECTING IONIC MATERIALS WITH REDUCED NOISE

摘要

An apparatus and a method of detecting ionic materials are provided to reduce electrical property differences between transistors in the ionic material detecting apparatus as well as to reduce noise. An apparatus of detecting ionic materials includes a sensing electrode(31), first to third switching transistors(TR1,TR2,TR3), a sensing transistor(STR), a voltage detector(33), and a voltage subtracter(35). The sensing electrode detects a sensing voltage by contacting liquid sample. The first switching transistor transmits the sensing voltage to a first node. The second switching transistor transmits a reset voltage to the first node. The third switching transistor connects the sensing transistor to the voltage detector. The sensing transistor is connected to the voltage detector and the third transistor and has a gate connected to the first node. The voltage detector detects a voltage applied to a gate of the sensing transistor. The voltage subtracter calculates a difference of voltages applied to the gate of the sensing transistor in sequence.