What is the principle of sine wave signal generating circuit?

Sinusoidal wave generator can produce sine wave output, which is formed by adding positive feedback on the basis of amplification circuit. It is the core circuit of various waveform generators and signal sources.

Sine wave oscillation circuit is composed of positive feedback network, amplitude stabilization circuit, frequency selection network and amplification circuit.

However, in order to generate sine wave, sine wave oscillating circuit must add positive feedback into amplifying circuit. Therefore, positive feedback network and amplification circuit are two indispensable components of sine wave oscillation circuit. Although the amplifying circuit and the positive feedback network are very important, it is difficult for the sine wave oscillator composed of these two parts to generate sine waves, because the amount of positive feedback is difficult to control.

If the positive feedback of sine wave oscillation circuit is large, its amplitude increase and output amplitude will be larger and larger. In the end, it can only be limited by the nonlinearity of triode, which will inevitably lead to nonlinear distortion. On the contrary, if the amount of positive feedback is insufficient, the amplitude will decrease and the vibration may stop. This is why the oscillating circuit must have a stable amplitude circuit.