Found in a 1924 publication, this 2-valve receiver has a speaker output. Power comes from several batteries. Information about the coils is given.
This high voltage regulator uses only two passive components. The output is 100 V, but replacing...
This circuit was found in a 80’s Popular Electronics. The components are common and the 8-ohm...
This 1964 Electronic Design circuit uses a photo-FET as a sensor. The component is rare today. |...