Hi all,
I am debuging a pH sensor. But while doing the same i could not understand what to the particular section of the circuit does. This has been maked in Red rectangle in the attached file.
The input of the sensor is -413 mv to +413 mv. As far as i understand, the first two op-amp just buffer the signal from the sensor. The measuring electode is been buffered with respect to the voltage at the reference point or the reference voltage of the sensor.
The second upper part takes the difference of it and since an another voltage is been appled (600 mv) for the offset, it would act a non-inverting summer to create a offset. But what does the lower part do?? If i remove it, the circuit doesn't work. Requesting the help.
I am debuging a pH sensor. But while doing the same i could not understand what to the particular section of the circuit does. This has been maked in Red rectangle in the attached file.
The input of the sensor is -413 mv to +413 mv. As far as i understand, the first two op-amp just buffer the signal from the sensor. The measuring electode is been buffered with respect to the voltage at the reference point or the reference voltage of the sensor.
The second upper part takes the difference of it and since an another voltage is been appled (600 mv) for the offset, it would act a non-inverting summer to create a offset. But what does the lower part do?? If i remove it, the circuit doesn't work. Requesting the help.
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