Low frequency voltage amplifier with low input amplitudes

The amplification of an electrical signal is an essential step in analog electronics, particularly for the recovery and processing of information from a sensor, antenna, or, more generally, a transducer. Without this function, variations in the observed signal (and therefore in the physical quantity) will not necessarily be perceptible, particularly due to the low amplitude at the sensor output, which makes subsequent processing impossible, but also due to the inevitable presence of intrinsic noise and parasitic signals.

In this article, we focus on amplifying low-amplitude voltages at low frequencies (LF) using operational amplifiers (OPAs). Our analysis is based on relatively accessible methods related to circuit theory (node law, mesh law, Ohm's law, etc.). Transistor-based amplification could have been discussed. However, this would have significantly increased the length of the document, making it difficult to read and the knowledge complex to acquire. However, some answers can be found at [E 2 427] and [E 2 430] . The study of amplifiers operating at high frequencies (HF) is based on more specific analysis methods, which no longer deal with voltage or current, and is not the subject of this article. If necessary, you can refer to the articles [R 310] , [E 1 428] , [E 1 610] , and