Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
This circuit is from General Electric documentation from 1970. The transistors can be of...
This sophisticated decade of benchtop resistors was found in the November 1989 issue of Radio...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern...