What is a requirement to sustain oscillations in an oscillator?

To sustain oscillations in an oscillator, positive feedback is essential. In the context of electronic circuits, positive feedback is the process where a portion of the output signal is fed back to the input in phase, which reinforces the signal. This characteristic is crucial in creating and maintaining oscillation because it allows the circuit to amplify its own output continuously.

When the feedback is positive, it enhances the amplitude of the oscillations over time until the limits of the circuit are reached. This ongoing reinforcement leads to a steady state of oscillation as long as conditions permit. Components like transistors and operational amplifiers utilize this principle in oscillator designs.

While negative feedback can stabilize a system and reduce distortion, it does not contribute to sustained oscillations—rather, it tends to suppress them. Stability of voltage and temperature control can be important for the performance of an oscillator, but they do not directly influence the necessity for positive feedback in the oscillatory process itself.