Found in a 90s Popular Electronics, this circuit excites a 40 kHz ultrasonic transducer. The transistor can be a BD135 or other medium power.
This transistor source was found in a 1990 documentation. 2N3055 transistors must be equipped with...
This circuit is implemented with operations that are not common today but can be assembled with...
We found this circuit in a 1977 Radio Shack manual. The light bands are given by the operating gain...