MrCoolGuy
Tele-Afflicted
If a fuzz pedal uses 2n3904 transistors... (a 2-transistor fuzz...) could you use bc109's instead? If not, why? They are both NPN... what am I missing?
Yeah, i kinda understand that... and im willing to change values as necessary...You can practically use any Si transistors you like for any fuzz, it’s just the biasing points and gain are going to be a little different. So you either have to tweak your resistor/coupling cap values, or maybe in some cases you want more or less of saturation/cutoff weird stuff.
Yeah, i kinda understand that... and im willing to change values as necessary...
But I swapped in some bc109's in this circuit (instead of 2n3904's which worked fine) just to hear the difference... but i get nothing. View attachment 923440
I hope I am making a simple mistake...Maybe a dumb question, but do you have the pinouts correct?
Yes. E-B-C. The collector has no insulator from the can.I hope I am making a simple mistake...
So, the tab is on the emitter side on these, correct?
Tab is pin#1=Emitter. pin#2 is Base, pin#3 = collector common to case.BC109 pinouts are C-B-E
2N3904 pinouts are E-B-C
In other words you may have put it in backwards ... remove, turn around and resolder.
What you say is correct, so I should perhaps rephrase or explain.Tab is pin#1=Emitter. pin#2 is Base, pin#3 = collector common to case.
https://my.centralsemi.com/datasheets/BC107.PDF
Well, sorry but I'm not the one confused. The OP said he had BC109's, not BC549's. BC109's are not BC549's.What you say is correct, so I should perhaps rephrase or explain.
I am in effect referring to the plastic TO-92 packages. I use those as my point of reference: flat face forward, pins facing down.
2N3904 = E B C TO-92A package (labelled as pins 1 2 3)
BC549 = C B E TO-92F package (labelled as pins 1 2 3) BC549 is the plastic cased (non mil-spec) equivalent of the BC109.
Some TO-92 transistors have a rear offset to the middle leg, making their footprint the same as metal can packages (direct drop in replacement).
So you can rephrase the BC109 as:
BC109 = C B E Emitter at Tab TO-18 package (Labelled as pins 3 2 1)
(From Wikipedia)
TO-18
(C-B-E)
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Emitter is closest to tab
I omitted the use of numbers to avoid adding confusion (which it seems to have done for you).
I stand behind my earlier post.