photographie par effet Kirlian

As with almost all self-driving `melody generators`, this circuit con-sists of a current-controlled oscillator and a control system. One possible approach would be to use a PLL (phase locked loop). A variant of the PLL concept is the sample-and-hold PLL, that has the advantage of being frequency sensitive to a sawtooth voltage. The `sawsong` is therefore a sample-and-hold PLL that is