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 can be used as shield or to drive powerful loads from low current switches such as...
This low power bass booster is from the 1977 National Semiconductor Audio Handbook. The circuit is...
This three-chanel remote control transmitter uses a unijunction transistor as low frequency...