Working‑Principle Analysis of H₂S Gas Detectors
Grasping the working principle of hydrogen sulfide gas detectors helps users achieve proper understanding of the equipment. Below is a detailed interpretation of its working principle.
The hydrogen sulfide gas detector adopts imported original amperometric electrochemical sensors, which generally consist of three electrodes immersed in electrolyte solution. The working electrode is fabricated by coating catalytic‑active metal onto a gas‑permeable yet hydrophobic membrane. The target gas diffuses through the porous membrane and undergoes electrochemical oxidation or reduction reactions. The reaction type depends on the thermodynamic potential of the working electrode and the electrochemical properties (oxidation or reduction) of the measured gas.
Electrons involved in the electrochemical reaction flow into (reduction) or flow out of (oxidation) the working electrode. The signal from the working electrode is amplified by operational amplifier U2 to form the output signal of the instrument. Meanwhile, the circuit maintains the voltage of the working electrode at the bias voltage VBIAS. The reference electrode supplies a stable potential for the working electrode in the electrolyte. After comparing the reference‑electrode potential with VBIAS, operational amplifier U1 outputs a voltage signal that generates an equal‑and‑opposite current signal relative to the working electrode.
The circuit maintains a constant potential difference between the working electrode and the reference electrode. The counter electrode is the second essential component of a complete electrochemical sensor, whose main function is to permit electrons to flow into or out of the electrolyte.
The above is the analysis of the working principle of hydrogen sulfide gas detectors. Users need to fully understand this principle and purchase products through professional and formal channels.
