Fairfield Circuitry 20% MoreExplorations around a schematic found among old papers of mysterious origin, suspiciously similar to a datasheet sq tri oscillator. All that was needed was to connect the dots. A slew limiter smoothes out how quickly incoming voltage can change, limiting it to a fixed v sec. slope. Since time and frequency are intrinsically linked, this acts as a steep, somewhat distorted low pass filter. When it resonates, these fixed slopes become triangle wave