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Projects => Beginner Project => Topic started by: pazuzu on November 07, 2009, 12:19:00 PM

Title: 2n3904 substitute?
Post by: pazuzu on November 07, 2009, 12:19:00 PM
got my futurelec order and no 2n3904.

a list of what i did get:

bc547
bc598
bc599
2n2222
bc107
2n2907
bc327
c9013
c1815
c4012
bc377? (printed c33725)
c338

can i sub any of these? i am going to start breadboarding everything else, help much appreciated guys. also if those transistors are useful in any other project i would appreciate a heads up so i can figure out my next endeavor, i got all the other grab bags so i prolly have the other components components.
Title: Re: 2n3904 substitute?
Post by: cpm on November 07, 2009, 12:51:57 PM
usually when a circuit ask for a 3904 you can put almost any npn with no big difference
Title: Re: 2n3904 substitute?
Post by: pazuzu on November 07, 2009, 01:02:36 PM
thanks. i just grabbed one of the 2n's for a mock up on the bread board. putting together my switch box right now and then i will put power to it. :)
Title: Re: 2n3904 substitute?
Post by: Gus on November 08, 2009, 11:47:22 AM
I you read through the threads about the NPN boost you should find posts about trying different NPN transistors.  People have even used Ge NPNs. The way the circuit is designed allows different hfe NPN transistors to "drop in" and have good operating points.  You need to know the pin out of the transistor and if it is NPN or PNP.
Title: Re: 2n3904 substitute?
Post by: pazuzu on November 08, 2009, 02:49:16 PM
well i assume the 2222 is npn since the circuit functions, although i haven't gotten far enough to know the difference.  :icon_rolleyes: to be honest i just lined the 3 points up like the circuit diagram when i bread boarded it (center pin left). 
Title: Re: 2n3904 substitute?
Post by: CynicalMan on November 08, 2009, 04:43:49 PM
I've seen places where the bc547 is said to be equivalent to the 2n3904. I think they are pretty close.
Title: Re: 2n3904 substitute?
Post by: pazuzu on November 08, 2009, 04:55:59 PM
cool man, i'll pop it in the bread board. the 2222 is performing just fine. fitted my 1/4"s and pot into the altoids tin ( :icon_rolleyes:), the only thing i am missing is board. i am debating whether i am going to make this off board tonight or wait. turned out nice though, i managed to locate the jacks on the side and still be able to close the lid.
Title: Re: 2n3904 substitute?
Post by: pazuzu on November 08, 2009, 05:12:29 PM
also a quick question, i am going to set this up as "always on" with no switch, wiring the ground of the battery clip to the 1/4" like always. if i want to add an led "on indicator" could i simply wire it onto the hot and ground with a resistor or do i need to buffer it some way?
Title: Re: 2n3904 substitute?
Post by: aron on November 09, 2009, 01:27:40 AM
Yes, you can wire it that way. The light will always be on when the unit has power.
Title: Re: 2n3904 substitute?
Post by: pazuzu on November 09, 2009, 09:06:43 AM
yep that's what i am going for. it's a novelty for me, i just wanted an led to make it flashy. i'll never use the thing since i play a solid state amp, with super heavy distortion, and active pups.

although i am considering a millenium bypass off a mini dpdt in the middle of the "O" in altoids. :icon_lol: