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 siren produces an intermitent sound given by the characteristics of the two oscillators using the...
This circuit for some amps was found in a 90s Radio Electronics. The voltage can be between 6 and 25 V...
This circuit was found in a 90s Electronic Engineering. The circuit has the tube's critical...