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.
Using the 2N2646 this circuit was found in a Radio Electronics magazine from July 1968. The...
The purpose of this circuit found in a 1990s Popular Electronics is to increase the current...
Found a documentation for PC from 1992, this circuit is indicated for the English power grid of...