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 circuit was found in a 1967 Raytheon manual. The transistors are from the time. Equivalent modern...
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The circuit presented generates short pulses. This configuration was found in a publication from...