In the figure we have a basic oscillator with inverters obtained from TTL, CMOS or other gates. The graph on the side allows to find the frequency depending on the resistor and the capacitor.
We found this CMOS circuit based on the PLL4046 in the December 1989 issue of Radio Electronics magazine....
The circuit shown in the figure has temperature compensation. Phototransistors can be of any type...
Found in a 90s 303 Circuits, this circuit triggers a load from a 50 mV audio signal. When the...