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.
This circuit controls a relay causing it to open and close its contacts at a speed that depends on the...
This circuit is from an Electronics World of 1968. The transistors are of the time and the power...
This circuit is from a Motorola manual from the 70s. The circuit can be implemented with more...