Found in an old English publication, this circuit applies to the 240 V network, but can be changed to lower voltages. Transistors are mostly general-purpose, admitting modern equivalents.
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...