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suitable germanium transistors for NPN


 :
11/21/1999 8:35 PM
nic
 suitable germanium transistors for NPN
Can anyone tell me what are suitable germainium NPN transistors for a fuzzface?  
 
thanks,  
nic
  
11/21/1999 10:07 PM
R.G.
According to Jack Orman, the 2N388A works well. I've tested those and about a dozen other types. The individual transistor seems to matter more than the type number.
  
11/22/1999 1:08 AM
Jack
Other good devices are the AC128, NKT275, 2N527 and the 2N508. But I agree that individual device characteristics are more important than the part number used.  
 
Recommendations are for a lower hfe device as the first transistor (80 to 100) and a slightly higher one as the second (over 100). You can often use your meter to select the devices from several samples of the same part number.  
 
regards, Jack
  
11/22/1999 2:02 AM
Mike Burgundy
Er, those are PNP Jack, not NPN. I'm not sure, but the AC127 might just be the NPN cousin of the 128.
  
11/22/1999 4:07 AM
Jack
you're so right, Mike. I didn't even notice that the question was about NPN as I was typing it in. So, here's some info that I had previously posted:  
 
Since the supply of 2N388A transistors have been depleted at Parts Express, I thought I'd post a few alternate devices  
that they carry that can be used for F-F construction.  
 
Part No. Type Hfe Price  
2N1306 NPN 100 $ .95  
2N1308 NPN 150 $ .75  
  
  
11/22/1999 4:47 PM
nic
howabout the NTE103 which is like $5 everywhere... Or the NTE103A which is $2 and seems to have the same characteristics of the AC128 aside from being NPN... Anyone try these?  
 
Thanks,  
nic
  
11/23/1999 1:03 AM
Jack
Or the NTE103A which is $2 and seems to have the same characteristics of the AC128 aside from being NPN..  
 
Other than being expensive, it can be used successfully. I made one with a pair of these and it was pretty good, although I have heard other people comment that theirs did not perform too well. As with the other transistors, the individual devices and the gain of each is more relevant to good performance. The "A" version of either the NTE103 or NTE102 will be better suited to the circuit.  
 
best regards, Jack
  

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