This stage was found in a 1964 Electronic Design. The transistors are of the time and the shape of the signal obtained is shown in the diagram.
We found this circuit in a 90's Radio Electronics. The low power circuit activates a 12 V relay...
This circuit sources a Constant current to a load. The current is determined by R2. In the...
This page shows a crystal oscillator for 2 MHz. Other frequencies can be produced depending on the...