This circuit has its frequency controlled by a 1MHz crystal. The circuit must be powered by a voltage of 5V. The capacitors must be ceramic. The generated signal is rectangular.
This basic configuration can be found in a lot of articles on this site. In this case, the relay...
This circuit is from American documentation from the 1980s. The transistors are general purpose...
The circuit is simple, as it uses only one transistor and a relay that can be MC2RC1 or MC2RC2,...