I have a circuit where I got the collector - emitter mixed up. Will the transistor work reversed?
MMBT3904 - 4.3v@ emitter (should have been collector).

Implemented as a signal switch, best thing is i got i right on a high side driver right next to the switch, cant believe i ballsed it up!

 

I'm no expert but from what I've read "NO"
The three have a specific function
Base,Collector, Emitter!
https://www.explainthatstuff.com/howtransistorswork.html

 

Yes, but very poorly. Beta as low as 1.

 

A BJT will usually work inverted but with very low gain.
Also beware that the max reverse Vbe is typically about 5V.

 

Yes, but very poorly.

Is that in all respects? mainly im only concerned about switching speed and as long as theres enough voltage for the micro to read the signal. stated switching is about 0.1ms rise and fall, theoretically i only need 15.0ms

 

A BJT will usually work inverted but with very low gain.
Also beware that the max reverse Vbe is typically about 5V.

Thanks crutschow, i think ill bite the bullet and give her a shot.
I've got 4.3v on the emitter so the reverse Vbe is 1.3v under the stated 6v

 

Why would you use it inverted is my question.
Why not just wire it up correctly. Did it blow something? Did what your trying to get to work , Not work?
just replace it and it will work as normal.
Maybe I need more knowledge but I didn't understand that's how they were suppose to work.

 

Why would you use it inverted is my question.
Why not just wire it up correctly. Did it blow something? Did what your trying to get to work , Not work?
just replace it and it will work as normal.
Maybe I need more knowledge but I didn't understand that's how they were suppose to work.

It wasn't intended to be used inverted, i made a mistake (or rather the software made a mistake)when I designed a PCB.
I Can not change the traces on a PCB, although id like to find one
I asked the question before blowing something up - trust me I'm No1 at that.

I read some posts that indicated some transistors are actually designed for inverse operation, so as usual came to the right place for the right info.

thanks all

 

From my fixing to put together my first project Transistors have very long connections. you can't just remove it and place another with the legs crossed so they're right? now not all of them but most. I couldn't fix my IC if I were to make a mistake on my PCB traces but transistors are different.
Just asking.

 

you can't just remove it and place another with the legs crossed so they're right?
Just asking.

NOT SMD
There may be a transistor with their PINS in different places but who's to know?

 

What are the exact part values and input signal level?

 

NOT SMD
There may be a transistor with their PINS in different places but who's to know?

Simply super-glue the part upside down on the board, and use 30 ga wirewrap wire to connect the proper pins to the proper pads.

 

I have a circuit where I got the collector - emitter mixed up. Will the transistor work reversed?
MMBT3904 - 4.3v@ emitter (should have been collector).

Unless you grossly over designed the circuit, no. Beta for inverted mode is very low.

 

Use 2SD2704K.
Brev~40 , Vbeo>25V