Virtual Laboratory Exercises Which Utilize Audio Signals to Enhance Understanding of Electronics Fundamentals

Abstract

Introductory analog electronics courses are traditionally considered among the most challenging in higher education curricula. Students usually encounter several key new concepts and paradigms, including incremental analysis of nonlinear electrical circuits and devices, as well as frequency domain analysis, time- and frequency-domain duality, filters, and signal filtering in general. Laboratory exercises serve as an indispensable tool to practically reinforce these concepts and diminish abstract barriers faced by first-time learners. However, they are often limited due to resource constraints. To address this challenge, a virtual laboratory exercise has been developed. This exercise demonstrates field-effect transistor amplifier quiescent point biasing, superimposed with a small audio signal and accompanying distortion. This implementation aims to bridge the gap between theory and practice, thereby enhancing students' insight into analog electronics. Implemented virtual laboratory exercises showcase (i) a common-source field-effect transistor (FET) amplifier with purely resistive load, and (ii) an RC-based first-order low-pass filter. These exercises enable the injection of not only generic audio signals like sine or square waves, but also samples from different music genres at the circuit input. Sound reproduction is supported for both the input and output signals. Amplitude and frequency of an input, as well as the resistor, capacitor, supply voltage, and simple switch unified MOSFET model values, are manually adjusted with the idea of observing the influence of gain, distortion and filtering. This facilitates a smoother transition between theoretical concepts, which often remain vague, and the actual, usually time-restrictive, laboratory demonstrations, thus boosting students' understanding.