With a 120 ohms resistor this circuit can also be used as a shield for 3.3 V output voltages. The circuit uses an opto-diac enabling the control of triacs connected to the power grid with total isolation.
This National Semiconductor circuit appears elsewhere on this site. The circuit must be powered by...
In this circuit the frequency is determined by the coil and the variable capacitor. Transistors like the...
This circuit is from old American documentation, but the transistor used is still very common...