The ports used in this ultrasonic remote-control transmitter are TTL, requiring a 5 V supply. The transducer is a piezoelectric type, not very common today.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...