This circuit was found in a publication by Edelman from 1924. The power comes from the battery and the listening is through a high-impedance headphone.
This circuit can be used in decoration or to draw attention, in a “fake” assembly for example. What he...
This sophisticated alarm with traditional components was found in an ancient American...
We found this AM radio in a 1957 transistor application manual, published by Raytheon. The...