Single op-amp sinusoidal oscillators suitable for generation of very low frequencies

The authors present some op-amp-based single-element controlled sinusoidal oscillator structures which can generate very low frequencies (VLF). In contrast to earlier VLF oscillators which have large frequency of the oscillations sensitivities and/or require two to five op-amps, the proposed circuits make it possible to generate VLF oscillations in a minimally sensitive manner while requiring only a single op-amp. The experimental results prove the validity of the theoretical formulations