We found this circuit in an old American publication from the 1980s. Transistors can be general-purpose types like the BC548, and the tuning frequency is given by the L and C components.
We found this circuit in a 1965 magazine. The circuit can be assembled with current equivalent...
This is a typical circuit of a PROM programmer from the 70s. It appeared in the magazine Radio...
If there is an indispensable household appliance in our kitchen these days it is the microwave...