In chemistry, pH is a measure of the activity of the (solvated) hydrogen ion. Pure water has a pH very close to 7 at 25°C. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.

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how to setup a ph sensor probe

I have a INA126 IN-Amp. I hope to use it with a ph probe. But I am not sure exactly how to do that. should I put the probe in series with a branch of a resistive wheat stone bridge, or just tie it to ...
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Tactics for stable unity-gain op-amp

The circuit given below is typical pH meter op-amp circuit. But here LMC6001 is not configured as unity gain. My question is this, I want to make this circuit with unity-gain buffer op-amp. What ...
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108 views

pH sensor project: trouble with RF interference

I built this pH sensor project on a breadboard and I'm having a big problem. The output on the voltmeter is completely erratic, and I'm pretty sure it's due to RF interference. When I connect the ...
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154 views

ESD protection for pH measurement electrode input

I want to puild a pH meter, which uses a normal glass electrode. Such an electrode behaves as a pH dependend voltage source (<+-500mV) with very high internal resistance (10MOhm - 1GOhm, depending ...
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467 views

Ground loop when measuring in process pH

I have been experiencing a very difficult to solve ground loop problem with my pH measuring system. My basic setup is a standard pH electrode running through an op-amp to an ADC which communicates ...
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Assistance with schematic notation “R@2V” for pH monitor

I've been building a circuit I found online for a pH monitor, while most of the circuit seems straight forward I get caught on the "R@2V" notation, a guess would be maybe resistance at 2 volts? I'm ...
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How do I hijack a reading from the circuit of my digital meter

I have a tri - meter (ph, ppm, temp) that reads and displays readings on three LCD screens. I'm trying to hijack the measurement at some point in the circuit and read it in through on of the inputs on ...
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pH sensor with DS18B20 temp compensation on PIC

I am trying to build a circuit that interfaces a standard pH electrode to a PIC (18F4550). I need the PIC to also use a DS18B20 for temp reading and use that data to correct the pH reading. I ...