Using JFETs, this circuit from a 90’s American documentation can generate signals of 0.15 Hz. The JFET can be of any general-purpose type like the BF245 or MPF102.
This simple circuit for motors that depends on the MOSFET used was found in the January 1998...
This transistorized shield also functions as a logic gate. The power supply can be in the range of 4.5...
Found in a 90s Popular Electronics, this Hartley oscillator uses an output transformer of the type...