Found in a 1980s American documentation, this circuit operates with 5 V signals requiring 55 cycles of 500 Hz for tone recognition. The circuit can be adapted to operate with other frequencies.
September 2017 - Mouser Electronics is announcing that it already have in its inventories the new...
Found in American documentation from the 90s, this circuit passes frequencies above 1 kHz. The...
This interference rejection circuit for telegraphy was found in a 1980s documentation for radio...