This circuit is from a 1967 documentation. It consists of a sensor for memories used at the time. It can be made with modern equivalent transistors. Note the 4 V symmetrical power source.
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...