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A signal conditioner for pH meter probe is required to have high input impedance. The signal conditioning of the pH meter probe is done by providing a buffer with gain, offset, and volatge to frequency converter. High input impedance requirement for pH probe while maintaining low cost constraint is given by 3130 CMOS opamp. Output of probe, is amplified by […]
Read moreA pH meter circuit is basically an amplifier to boost a voltage signal which is produced by a pH probe. The pH probe itself is equal to a battery cell when submersed in the measured solution, producing a weak voltage and current signal. High input impedance requirement for pH probe while keeping the cost low, a 3130 CMOS op-amp give […]
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Buffer amplifier is required by a typical pH probe to isolate its 10^6 to 10^9 ohm source resistance from external circuitry. Such an amplifier is shown in the following figure. The voltage error produced by the bias current and electrode resistance is minimized by the low input current of the AD795JR. To minimize leakage, we have to use guarding, shielding, […]
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What is A pH Meter? A pH meter is actually a precise voltmeter that measures the generated voltage of a pH electrodes. The requirement of such meter is high input impedance and has the gain of voltage-pH conversion. The standard pH probe generate voltage about 59 mV per pH, so all we need is a pre-amplifier with high impedance input […]
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