Low noise, open-source QEPAS system with instrumentation amplifier
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Updated: Jan 29, 2026

Building An Open-source Robotic Stereotaxic Instrument
Published on: October 29, 2013
Mateusz Winkowski1, Tadeusz Stacewicz2
1Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland. mateusz.winkowski@fuw.edu.pl.
Abstract:
Quartz enhanced photoacoustic spectroscopy (QEPAS) is a rapidly developing, ultrasensitive method for trace gas sensing. Adequate electronic amplifier, well matched to the quartz characteristics is crucial for overall system performance. Here we present an open source circuit for QEPAS signal amplification. It consists of a buffer, instrumentation amplifier and digitally controlled gain stage. An experiment showed, that it offers signal to noise ratio of about 23 dB better than commonly used transimpedance amplifier. The use of this circuit provides opportunity to improve QEPAS sensitivity by about one order of magnitude.
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