Using Guitar Pedals to Introduce Amplifier Design and Printed Circuit Board Layout in an Electronics Course

Abstract

One of the foundational learning outcomes of upper level engineering electronics courses is the analysis and implementation of discrete amplifier design. While it is relatively straight-forward to implement these designs in the lab, the application of amplifiers in practice may be difficult for students to understand.A simple application of discrete amplifier circuits is the analysis and design of guitar effects pedals. Effects pedals, and in particular overdrive, fuzz, and distortion circuits, demonstrate keystone concepts of electronics, including single stage amplifier design, multistage amplifier design, clipping, biasing, and variable parameter control. In addition, the implementation of these amplifiers in a small package size (within a metal enclosure) provides an excellent avenue for exposing students to printed circuit board (PCB) layout and prototyping. One benefit of these circuits is that they can be used with an input device (guitar) and an output device (audio amplifier) and students can physically observe (and hear) the results of their design. One particular benefit of this approach is a greater understanding of frequency response characteristics, as students are able to hear the results.In this work, several lab projects were developed for an upper level engineering electronics course to leverage guitar pedal design for teaching discrete amplifier design and PCB layout. This paper presents these projects, resources for implementing the projects, as well as assessment results from the initial offering of this course. In addition to direct assessment of the amplifier design course objectives, qualitative student survey results are presented. Both the direct assessment and student survey results suggest that this approach was effective in helping students better understand amplifier analysis and design.