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.
Two 3-terminal regulators like the LM317 can be used to "clip" a sinusoidal signal, in order to...
This 7400 TTL circuit has a memory, keeping the LED on when a pulse is detected. The circuit must be...
This sole beacon which has a battery charged by photocells was found in documentation from 1991....