Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz operating on the third harmonic. The transistor admits equivalent.
The integrated circuits used in this 1989 project are uncommon today, including the IF coil that...
This circuit was found in a 1968 documentation. It makes use of both NO and NC reed-switches and small...
This delay circuit for a sound system was found in the December 1990 Radio Electronics magazine as part...