Multiloop Feedback Compensation-Based Photometer Circuit

A photometer circuit based on a multiloop feedback compensation (PCBMFC) is presented. This circuit employs both positive and negative feedbacks, operates in a fully linear photovoltaic mode, and can be utilized to perform high-precision measurements. Prototypes of PCBMFC were built using both the AD820 precision operational amplifier (op-amp) and the TL084 general-purpose op-amp. The performance of PCBMFC and the performance of the classic photometer circuit (CPC) based on the transimpedance amplifier (TA) were compared with each other through laboratory experiments. A comparison of the error energy of measurement revealed that CPC is 2.2982 times worse than PCBMFC when using the AD820 op-amp, and CPC is 482.1006 times worse than PCBMFC when using the TL084 op-amp. Furthermore, the circuit robustness improvement against external disturbances of PCBMFC versus CPC was demonstrated throughout simulations. Moreover, a Wilcoxon signed-rank test (WSRT) showed that there were statistically significant differences between CPC and PCBMFC at both the 1% and 5% significance levels.