This alarm circuit was found in April 1975 Radio Electronics magazine. The circuit uses a 12 V power supply and relay but can be modified to work with other voltages.
Found in American documentation this circuit uses transistors of the time. The circuit can be made...
This flasher with two power transistors was found in a Radio Electronics magazine from September 1961....
Found in American documentation from 1969, this circuit switches signals with a FET of the time....