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.
This circuit is interesting for experiments and can be part of the bench in the form of a module. The...
Constant currents from 10 mA to 1 A can supply the load, depending on the selection made by S1. Q1...
In the figure we have the transmitter and the receiver for an optical audio link via infrared. The...