Sinusoidal oscillators and multivibrators are not separate classes of circuits

When multivibrators are forced to operate at high frequencies one usually observes transition from relaxation to sinusoidal oscillations. One considers that at these frequencies the parasitic capacitors of active devices become comparable with functional capacitors, and the effect of parasitic produces this ldquosmoothingrdquo of oscillations. This paper considers a counterintuitive example: the oscillator where the transition goes in opposite direction. The operation starts from sinusoidal oscillations at low frequencies. Reducing the functional capacitor value one obtains relaxation oscillations at higher frequencies. This example shows that oscillators and multivibrators are not separate classes of circuits.