Found in a 1965 CQ magazine, this circuit uses period components. The unijunction transistor can be a 2N2646 and the relay has voltage according to the supply.
This two-transistor MW radio was found in a publication from 1958. It uses one of the oldest type...
Found in a 1988s Radio Electronics, this circuit uses transistors of general use to increase the...
This circuit can be applied to other 3-terminal regulators and equivalent transistors can be used....