A Voltage Controlled Oscillator for your lab #electronics #VFO

A full triangular waveform #VFO is presented and explained in this video.
Unlike the well known 555 IC that can be used also as Voltage Controlled Oscillator, the circuit presented in this video features much better characteristics, both for the range of frequencies (a full one order of magnitude for every single range) and for the quality of the generated waveform, low noise and perfect straight slopes of the triangular wave.
This circuit is the starting point for future developments that will be presented in next episodes, with the aim to achieve a complete instrument for the laboratory of electronics.

For further reading I recommend to read the description of the HP generator Model 3311A presented by Hewlett-Packard in its own publication “Hewlett-Packard Journal” on July 1973. Although the circuit is substantially different from the one showcased in the video, both start from the same concept of charging/discharging a capacitor through a variable voltage source driving a constant current source.