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.
Found in a 1969 EDN, this circuit uses components from that time. Modern equivalent transistors can be...
This amplifier with old germanium transistors is from a 1957 documentation. The power is a few...
We found this circuit in an American documentation from the 90s. The circuit combines functions of 4...