What is the composition of the air detector sensor - Product News

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What is the composition of the air detector sensor

Our Admin
2018-01-17
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pm 2.5 monitoring


An air detector sensor is usually made up of three electrodes, the most important of which is the working electrode. It is usually made of a metal with catalytic activity, such as platinum, that is sprayed on a breathable but hydrophobic film. The measured gas diffusion is oxidized or reduced through a porous membrane. The properties of the reaction are determined by the thermodynamic potential of the working electrode and the properties of the analysis of the gas (redox). The electrons in the redox reaction, the flow (reduction) or the outflow (oxidation) working electrode, are the output signals of the sensor by the external circuit. The thermodynamic potential of the working electrode is a very important factor in order to carry out the redox reaction. The reference electrode is designed to provide a stable potential of the working electrode in the electrolysis. The reference electrode usually needs to be protected so that it is not exposed to the sample gas so that the thermodynamic potential of the reference electrode is always stable with the same value. In addition, the reference electrode does not allow the second electrode to be required by the current, and its function is to allow electrons to enter or flow out of the sensor.

A circuit (or a constant potentiometer) that controls the electric potential of the working electrode and the circuit that converts the signal current into a voltage signal. The working signal of the working electrode needs to be converted to the voltage signal via the operation and release U2. The circuit keeps the voltage of the working electrode at the value of its bias Vbias at the same time. The reference electrode potential is compared with a carefully selected stable input voltage Vbias. In the line, Op Amp U1 generates a voltage signal on the counter electrode, which is just the same as the current of the working electrode. At the same time, the constant potential circuit keeps a constant potential difference (voltage) between the working electrode and the reference electrode

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