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 small automotive NiCad battery charger uses only passive components and has the number of...
This circuit is from a publication from the 50's. Inductive components are critical, and...
Found in documentation from the 1980s, this circuit can generate signals between 6 and 8 MHz. The...