We found this circuit in an Electronics Now magazine from June 1995. The transformer has a primary according to the network and a secondary of 6 to 9 V with 100 mA.
This circuit was found in a 1966 EEE. What it does is it converts the logic levels of 0 V and +4 V...
This circuit has been found in operational documentation of the 1970s. The circuit has a fail-safe...
This simple circuit does not use active components and uses a small speaker as a microphone. The...