bc109B marking and bc109c marking???

[garfo]

What is the difference between the marking on the bc109 transistors.Why some have B and others have C, does this have anything to do with gain?

[pickdropper]

What is the difference between the marking on the bc109 transistors.Why some have B and others have C, does this have anything to do with gain?

It does. There are gain ranges for A, B and C.

If you google BC109 datasheet, you can find it fairly easily.  The datasheet breaks down the gain ranges for BC108 and BC109 and includes references to the A, B and C suffixes.

[garfo]

so,i suppose B will be lower gain from what ive read,right?

[pickdropper]

Usually, yes.  It is a lower gain bucket, but there is some crossover, so if you get a B with the max gain and a C with the min gain, the B could have more (albeit not much).