Generator Colpittsa (1)

The most popular (and not without reason) sinusoidal LC generator. A very simple structure, but a very difficult circuit to understand and run. Before watching this video, I suggest you watch the previous videos in this playlist – about resonant circuits and the resonant amplifier. The basic principle of operation of such a generator is simple: a resonant amplifier + a positive feedback loop. And one more thing, not immediately obvious: a divider (in the Colpitts, a capacitive one). Why a divider? Well, to pre-reduce the gain (usually significantly too high) in the closed positive feedback loop. And you'd think that would be all... Unfortunately, not. The main problem with these generators is usually overlooked in general academic studies. It's a matter of setting the oscillation amplitude so that the signal isn't distorted. And that's really difficult. But I'll try to explain anyway... Aleksander Burd