This traditional signal injector configuration was obtained in a 1977 amateur radio manual. The frequency is given by the capacitors and the supply can be made with 1.5 or 3 V.
In the figure we have the way to activate a red LED that needs 1.7 V or even others with higher...
Found in a Popular Electronics - January/February 1969 this circuit was intended to increase the...
This circuit can be used as a residential doorbell. We found it in an English publication from...