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Re: C557B? transistor/1/2V ->base?


 :
5/21/1999 12:36 PM
aron

 Re: C557B? transistor/1/2V ->base?
Thank you!!  
 
The problem was that I found the cross-reference in the nte lookup but they changed the pinout so I didn't know the original pinouts.  
 
I didn't want to take the transistor out (last resort) to measure it on my DMM.  
 
Can this be correct? On this pedal, I swear that voltage is fed into the Base, the collector goes to ground and the emitter is connected to the output of an op amp...  
 
I measured 1/2V going into the base when the circuit is running.  
 
Thanks,  
 
Aron
  
5/21/1999 1:06 PM
R.G.
If the device is a PNP, with a collector tied to ground and the base tied to a voltage, and the emitter is connected to pin 1 of a *single opamp*, then it might be working correctly for a PNP.  
 
Of course, I don't know what circuit you're working with, so that's just a guess 8-^)
  
5/21/1999 9:36 PM
aron
The device is PNP, the collector is tied to pin 5 (offset NULL) of a TL071, the base is tied to voltage and the emitter is tied to the output of the op amp.  
 
Ahhhh. Pin 1 is the same as pin 5. Yes, yes, that's it!  
 
But, according to the pinout, I *think* that the emitter is tied to the output of the op amp.  
 
Aron  
 
R.G. Check your email-box for an updated schematic (hand drawn).
  
5/24/1999 8:42 AM
Gus
Aron Email me an schematic if you don't mind. Thanks  
 
Gus
  

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