MG811

www.DataSheet4U.com MG811 CO2 Sensor Features Good sensitivity and selectivity to CO2 Low humidity and temperature dependency Long stability and reproducibility Application Air Quality Control Ferment Process Control Room Temperature CO2 concentration Detection Structure and Testing Circuit Sensor Structure and Testing Circuit as Figure, It composed by solid electrolyte layer £¨ 1£ © £ ¬ Gold electrodes £¨ 2£ © £ ¬ Platinum Lead £¨ 3£ © £ ¬ Heater £¨ 4£ © £ ¬ Porcelain Tube £¨ 5£ © £ ¬ 100m double-layer steeless net £¨ 6£ © £ ¬ Nickel and copper plated ring £¨ 7£ © £ ¬ Bakelite (8)£¬ Nickel and copper plated pin£¨ 9£ © ¡ £ Figure 1A Figure 1B Working Principle Sensor adopt solid electrolyte cell Princip le£¬ It is composed by the following solid cells£º Air£¬ Au|NASICON|| carbonate|Au, air£¬ CO2 When the sensor exposed to CO2£¬ the following electrodes reaction occurs£º Cathodic reaction£º 2Li + + CO2 + 1/2O2 + 2e - = Li2CO3 Anodic reaction£º 2Na+ + 1/2O2 + 2e- = Na2O Overall chemical reaction£º Li2CO3 + 2Na + = Na2O + 2Li + + CO2 The Electromotive force £¨ EMF£© result from the above electrode reaction, accord with according to Nernst’ s equation:£º EMF = Ec - (R x T) / (2F) ln (P(CO2 )) P(CO2 )¡ª CO2--- partial Pressure Ec¡ª Constant Volume R¡ª Gas Constant volume T¡ª Absolute Temperature £¨ K£© F¡ª Faraday constant From Figure 1B£¬ Sensor Heating voltage supplied from other circuit , When its surface temperature is high enough , the sensor equals to a cell, its two ...