BC557, what I can do with them?

[Marcos - Munky]

I found 18 BC557s in a old board, what I can do with them?

[Ge_Whiz]

BC557 - general-purpose silicon PNP transistor, gain probably ~200. Complementary PNP device to BC547 (NPN), which is a modern version of the old BC107.

[BillyJ]

What are the BC107's good for? I just got ahndful from the local surplus. They just looked cool to me.
I tried them in place of a 2n3906 the other day and it sounded pretty good. I may keep it there.
Was curious if they are good for anything particular?
Thanks!

[Marcos - Munky]

Anyone know some circuits that I can use the BC557?

[Ge_Whiz]

BC107 is a lower gain but higher voltage version of the BC108/BC109. The extra voltage handling is of no consequence for stompboxes (unless you like to risk electrocution). You can use them as general purpose NPNs in place of (say) 2N2222. Most distortion units will happily accept them. They will sub for BC108 or BC109 in a silicon fuzz face, for example. The only reason for specifying the BC108 instead is that, because of the voltage ratings, the BC108 was a cheaper device in bulk.

Similarly, you can use BC557s as GP PNPs - trouble is, how many circuits use PNP silicon trannies? Not many.

[Marcos - Munky]

Thanks.

[BillyJ]

Yes thank you!!