Topic 83: BJT, MOSFET, Triode Distortion Comparison/Analysis

🔊 Why Do BJTs, MOSFETs, and Triodes Sound Different? In this video, we take a deep, first-principles look at one of the most important—and often misunderstood—questions in analog electronics and audio: Why do different devices produce different types of distortion? By comparing the transfer characteristics of BJTs, MOSFETs, and vacuum tube triodes, we uncover how their fundamental device physics directly shapes the output waveform and harmonic content. We examine: BJT exponential behavior MOSFET square-law characteristics Triode 3/2 power-law response Using these models, we derive approximate transfer functions and analyze how each device responds to a sinusoidal input. This allows us to predict and understand the resulting nonlinear distortion—before ever looking at a spectrum. To validate the theory, we compare: Analytical predictions Simulated waveforms Real oscilloscope measurements This provides a complete picture of how device physics translates into measurable—and audible—differences in amplifier behavior. 🔧 Topics Covered BJT exponential transfer function MOSFET square-law behavior Triode 3/2 power-law characteristics Nonlinear distortion modeling Harmonic generation from transfer functions Waveform symmetry and distortion Analytical vs simulated vs measured results 🧠 Engineering Approach This material is presented using a rigorous, first-principles engineering methodology: Device physics → transfer function → waveform → distortion Power-series / binomial expansion techniques Avoiding black-box assumptions Direct comparison across device technologies Validation through simulation and real measurements 📌 Why This Matters This analysis provides a unified framework for understanding distortion across all major device types, giving you the tools to predict how circuits will behave—and why they sound the way they do. 👍 Support the Channel If you’d like to support the channel and help fund future content, consider becoming a patron: 👉   / electronics4guitarists   #Electronics #AnalogDesign #Distortion #VacuumTubes #MOSFET #BJT #CircuitAnalysis #AmplifierDesign #ElectricalEngineering #GuitarAmplifier