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.
This circuit was found in a 1967 US documentation. The circuit applies to modern general purpose...
Found in a 90s Popular Electronics, it serves both TTL and CMOS logic. The injector can provide 10...
This VHF receptor was found in a Japanese publication from the 1960s. The original transistors can be...