This simple circuit with a 5V regulator was found in an American documentation from the 90's. The output voltage is adjusted in a trimpot.
This circuit was found in Linear Technology Applications of 1997, using components of the time. The...
This cricket circuit obtained in a 1992 documentation has an amplifying stage that, however, takes...
With this circuit, a common multimeter can be used to check if there is a microwave leak in a...