The transistors of this circuit found in an English 1980s documentation may be the modern BC548 equivalents. The circuit is battery powered and the earphone must be crystal.
This circuit is based entirely on SCRs. The circuit is from an American 80's documentation; and the PUTs...
The integrated circuits used in this 1989 project are uncommon today, including the IF coil that...
September 2016 - Mouser Electronics already has the new TPS54335-2A from Texas Instruments...