Found in documentation from the 1980s, this circuit can generate signals between 6 and 8 MHz. The frequency can be slightly varied in the setting. FET is a general-purpose type.
The basis of this circuit is a CA3130 operational amplifier. The transistor can be BC548, and the...
This circuit, found in a 73 magazine for radio amateurs, is used in radio localization. The...
This circuit is from an American magazine Popular Electronics of March 1991. The circuit produces both...