This well-known circuit version of the siren was obtained in a Colectro Handbook from the 70s. The transistors are of general use, with Q2 being a BD136 for greater power with power from 6 to 12 V.
We find this vibrato configuration with transistors in a 1987 documentation. The components are still...
This circuit was obtained in a 1967 Electronics World. The components are still common today, the...
We found this voltage regulator for 5 V with current up to 10 A in an old manual of integrated circuits....