It’s a saw-core oscillator with a triangle converter, a sine converter and a square-wave too. The square has pulse width control and CV input. Saw-core was the best way I could implement hard sync. When the sync input goes high, all waveforms hit their minimum; this was implemented to function as a reset when in LFO mode. The coarse tune runs all the way from 0.1 Hz to over 15 kHz. The trimpot visible on the face is for calibrating volts per octave, and it should be stable across ten octaves.

Analog oscillators are sensitive to the ambient temperature, and often have temperature compensation circuits. The Karltron uVCO is designed to support several schemes of temperature compensation because the specialized parts are sometimes hard to find. There’s a spot for a PTC resistor if you have one of those, or an NTC resistor if you have one of those, or it could be built with no compensation and tuning that needs recalibration with the season.