LTspice Study Compares I-V Characteristics of BJT and MOSFET Transistors

A study used LTspice simulation software to analyze and compare the electrical characteristics of two fundamental transistor types: the BJT and the MOSFET. The BJT, a current-controlled device, showed flat collector current curves in the active region with evenly spaced intervals as base current increased, reflecting a consistent amplification ratio. The MOSFET, a voltage-controlled device, exhibited nonlinear square-law behavior, with drain current curves spacing out increasingly wider as gate-source voltage rose in equal steps. Physically, the BJT relies on minority carrier diffusion through a thin base region, while the MOSFET operates by forming an inversion layer channel via a gate-induced electric field. The experiment highlighted key differences in how each device controls current, underscoring their distinct roles in electronic circuit design.