Found in a magazine 73 for radio amateurs, this circuit makes use of general purpose transistors and the integrated circuit is still easily found.
This circuit converts inductances on two scales into voltages. The circuit was obtained from a...
Placed in the vicinity of a telegraphic transmitter (CW), this circuit produces an audible signal on...
This circuit was found in a 1967 RCA documentation. The components are of the time. The circuit...