Transistor Cross Over

[Warlord]

Building a Fog Horn for my light house and I need replacement transistors for a BC547 and a BC 557. I have done Google searches but but have only been slightly helpful.

 

[(*steve*)]

Both BC547 and BC557 are readily available.

They are jellybean components and it is unlikely they were chosen for any particular reason (other than being common).

If you have a copy of the schematic we can tell for sure, but you can try any small signal NPN and PNP transistor. A 2N3904 and 2N3906 may be suitable.