Seminar Details
2026-02-17 (11:00) : Noise feedback in circuits and application to the design of a noise-based amplifier
At Nyquist
Organized by Electrical Engineering
Speaker :
Bertrand Reulet (Université de Sherbrooke)
Abstract :
Electronics is based on the idea that the current-voltage characteristics of a component are intrinsic and do not depend on the circuit the component is embedded into. This idea makes it easy to simulate and build circuits based on the characteristics of the individual components. We show that this is incorrect, because of noise feedback. The effect of the circuit is to transform the current fluctuations generated by each component into voltage fluctuations across itself. This feedback mechanism leads to changes in the current-voltage characteristics. We provide a simple theory to describes this as well as an experiment on an avalanche diode to confirm it. Then we build an audio amplifier where the noise feedback mechanism leads to a region with negative resistance in a Zener diode, which we use to build an audio amplifier.