Suggested by an old RCA manual, this circuit makes use of the period components. Data for the transformer is provided in the original documentation from the 1960s.
This simple metal detector was found in a 1960 Sylvania transistor manual. The phone must be high...
This is one of the many versions of this type of indicator that the reader can find on our...
Found in an English publication from the 1980s, this circuit can be built with equivalent...