Found in documentation from the 1980s, this circuit can generate signals between 6 and 8 MHz. The frequency can be slightly varied in the setting. FET is a general-purpose type.
This is a reservoir level control project, in this case, using 4 sensors so that 4 different...
Found in a 90s Popular Electronics, this circuit excites a 40 kHz ultrasonic transducer. The...
This circuit, from a 1986 Texas manual, appears elsewhere on this site, including in the form of a...