| 摘要 |
PURPOSE:To effectively improve responsiveness by changing a monitor voltage according to the output current of a sensor corresponding to a specific gas concn. and adjusting the difference in the monitor voltage between the case in which the specific gas concn. is 21% and the case in which said concn. is 0% to a prescribed voltage of 0.2-1.0V. CONSTITUTION:The sensor output current Is detected by a sensor current detecting circuit 7 corresponds to the concn. of the ambient gaseous oxygen. This current Is is fed back to a monitor voltage setting circuit 6. The circuit 6 changes the monitor voltage Vs in accordance with the fed back current Is to increase the voltage Vs when the current Is increases with an increase in the oxygen concn. and to conversely decrease the voltage Vs when the current Is decreases with a decrease in the oxygen concn. The circuit 6 sets the voltage Vs (Air) when the gas to be measured is air, i.e., when the oxygen concn. is 21%. The circuit sets the voltage Vs (N2) when the gas to be measured is pure gaseous nitrogen, i.e., when the oxygen is 0. Furthermore, the circuit changes the voltage Vs linearly from Vs (Air) to Vs (N2) according to a linear change in the oxygen concn. from 21% down to 0%. The responsiveness is thus improved. |
