modified 3 years ago

Inductorless resonator

00:43:10

Not sure exactly what I ended up with here. Somehow I made a resonator. It makes me think that the circuit to the right of the blue wire mimics an inductor, but it doesn’t actually. Yet somehow it resonates with a very high Q when I add the capacitor on the left of the blue wire. Maybe this could have applications for high-Q resonance in situations where inductors are impractical?

published 3 years ago

592azy2circuitdude

3 years ago

Swell circuit 👍. I'm by no means an expert on oscillators, but your circuit looks a whole lot like a Buffered Phase-shift Oscillator, or a Quadrature Oscillator to me. My understanding is that the capacitors shift the signal gradually so that positive feedback is created back at the input. An online article by TI called "Design of opamp sine wave oscillators" describes some circuits similar to yours. I hope this is helpful.

592azy2circuitdude

3 years ago

Uh I just realized that you said "resonator" not "oscillator". I don't know if those are the same thing or not. Sorry if I caused any confusion!

jason9

3 years ago

Actually, when you said oscillator it made me realize this is in fact an oscillator! It had been so long since I touched circuitry that I seem to have forgotten that a resonating system with amplifiers in it is actually just an oscillator with exactly unity gain at the frequency of oscillation. Slightly increasing the gain makes it self-oscillate, and decreasing it makes it a damped resonator.

jason9

3 years ago

So, this circuit isn’t actually that special besides the unusual topology. Most oscillators can be made to act as a resonator by tuning the gain to be at or just below the oscillation threshold.

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