A Temperature Compensation Circuit of Oxygen Sensor

Abstract

The invention discloses a temperature compensating circuit of an oxygen sensor. The temperature compensating circuit is as follows: an electric resistor R3 and an electric resistor R2 are connected in series between a positive electrode and a negative electrode of the oxygen sensor, the positive electrode of the input end of a primary operational amplifier is connected with a node between the electric resistor R3 and the electric resistor R2, an electric resistor R4 and a thermistor R5 are connected between the negative electrode F of the input end of the primary operational amplifier and the ground, two ends of a filter circuit are connected with the negative electrode of the input end and the output end of the first operational amplifier, the output end M of the primary operational amplifier is connected with a secondary operational amplifier in series, the positive electrode and the negative electrode of the power supply pin of the secondary operational amplifier are respectively connected with +5V power supply and -5V power supply, the output end N of the secondary operational amplifier is connected with the positive electrode of the input end of a liquid crystal display, and the negative electrode of the input end of the liquid crystal display is grounded. The temperature compensating circuit has the beneficial effects that electronic parts are adopted to form the temperature compensating circuit, the oxygen sensor is not affected by environment with high and low temperature after suitable thermistor resistance value is selected, and the temperature compensating circuit has the advantages of stability in working and high precision.

Description

technical field [0001] The invention provides an oxygen sensor, and particularly relates to a temperature compensation circuit of the oxygen sensor which can offset the influence of the external temperature on the measurement accuracy of the oxygen sensor. Background technique [0002] The oxygen sensor in the oxygen and carbon dioxide detector is dedicated to the detection of oxygen content, that is, the magnitude of the passing current reflects the amount of oxygen content. The principle is: the inside of the sensor is a sealed container, which contains two electrodes ( cathode and anode) and the electrolyte in which the reaction takes place. When the external oxygen reacts with the electrolyte through the capillary pores of the oxygen sensor, different ionized ions are dissociated to the two electrodes respectively, forming a current. The size of the current is proportional to the size of the oxygen content, and the size of the current reflects the amount of oxygen conte...

AI Technical Summary

Problems solved by technology

Under the influence of temperature, the above-mentioned oxygen sensor shows that the current value is unstable, which directly affects its measurement accuracy.

[0005] Because the output current of the oxygen sensor itself is very small, its output current must be amplified by a certain number of times through an external circuit in actual use, and because the size of the current is proportional to the size of the oxygen content, the output current of the oxygen content after the amplification circuit There must be more errors

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