Tham khảo tài liệu 'polymer thin films part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 264 Polymer Thin Films Typical noise of the LF 356 is specified LF356 LF357 JFET 2001 as eni 12nV Hz and eno 80nV Hz . Total noise RTI and RTO of the LF 356 operating at a gain of 10 is equal to RTI 14 42nV JHZ RTO 144nV JhZ Also the noise input current of the LF 356 is very low pA y Hz . Another design for this conditioning CO2 transducer amplifier is showing in Fig. 15. The AD 8224 can operate on a 15 V dual supply. The most important parameter for this application is common - mode rejection ratio CMRR . The AD 8224 has a high CMRR of 94 dB for G 10. In addition slew rate of the AD 8224 is 2V ps and the transfer function Charles Kitchin and Lew Counts 2004 . G1 1 ------- respectively R1A R1B 8 Fig. 15. Precizion AD 8224 JFET Input instrumentation amplifier for CO2 transducer interface. G 2 1 Placing a resistor across the R1A and R1B terminals sets the gain of the AD 8224. For best performance by using standard value of 1 resistor R1A R1B KQ calculated gain is . For optimum performance a low - pass R - C network can be placed at the input of the instrumentation amplifier. This filter limits the input signal bandwidth according to the following relationship Charles Kitchin and Lew Counts 2004 FilterFreqDiFF 2 A 2C 2A C1A Organo-siloxane supramolecular polymers used in CO2 detection-Polymer thin film 265 where C1A C 3 A and R2 A R3 A 10 As shown R2A R3A can be metal film resistors and C1A C3A 1nF C 2 A 10nF miniature size micas. Fig. 16 presents the ansamble of image for CO2 detector. As shown in Fig. 16 this application required a variable gain amplifier. Fig. 16. The image of CO2 detector 5. Theoretical aspects of equivalent scheme . General equivalent circuit of active sensor As a first step in the direction to make clear the study of gas sensor is following classification a Active sensor and represents a sensor which convert the gas effect of the sensible material in a microvoltage -Fig. 17. Example gas .
