some general transistor questions

Started by bonkdav, December 23, 2007, 02:47:58 PM

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bonkdav

ive been collecting germanium transistors since ive started my stompbox journey and im finally getting motivated/educated enough to to test them for leakiness and gain and apply this to circuits.  The only problem is there are quite a few random ones or groups of them that i have no info on.  I was just wondering if there was any way a transistor could be identified as npn or pnp and also if there is a way to figure out the pinout after that since some i already have labeled.

also if im testing npn transistors what alterations do i need to do to R.G.'s process illustrated in the technology of the fuzz face.(i want a neg ground fuzz face that can go off my power supply so it will be easy on the pedalboard)

ive tried some searching but it hasnt worked out yet.  Any help would be greatly appreciated. Thanks.

Davis

kurtlives

This helped me a lot...http://www.diystompboxes.com/smfforum/index.php?topic=63617.0

Do they not have little dots on the sides or tabs to tell whch leads are which?

As for testing which are which I usually test them in my DMM. If I put it in the NPN and don't get a reading it is a PNP.

To test NPNs just flip the leads of the battery and the DMM's leads.
My DIY site:
www.pdfelectronics.com

bonkdav

Thanks for info, a lot of that was really helpful. my dmm doesnt do transistors. i guess ill have to look up data sheets and or start searching for markings.  im pretty stoked on the fuzz builds im about to do.  Some good and proper germ.

kurtlives

Cool I just built a tester to test a huge bunch of bunch of AC125s I got. I don't know what to use them in though. Any ideas...?

My tester...
My DIY site:
www.pdfelectronics.com

culturejam

Quote from: bonkdav on December 23, 2007, 06:41:17 PM
my dmm doesnt do transistors.

Then get one that does! I got one for $25 that does transistors (hfe), diodes (forward voltage), and capacitors, in addition to resistance, AC and DC. I actually saw one in AutoZone that did transistors and diodes (don't recall if it did capacitance testing) for about $20.

Now,  I check every single component before soldering, and matching transistors for gain is trivial.

kurtlives

Quote from: culturejam on December 24, 2007, 12:55:42 PM
Quote from: bonkdav on December 23, 2007, 06:41:17 PM
my dmm doesnt do transistors.

Then get one that does! I got one for $25 that does transistors (hfe), diodes (forward voltage), and capacitors, in addition to resistance, AC and DC. I actually saw one in AutoZone that did transistors and diodes (don't recall if it did capacitance testing) for about $20.

Now,  I check every single component before soldering, and matching transistors for gain is trivial.
I got my DMM for $10 and it measures hFE, diodes etc...
My DIY site:
www.pdfelectronics.com

culturejam


petemoore

  I get 'em for 3.88.
  First thing I do is run the cables to the top and under a tight band of electrical tape.
  When the battery door dies [like try to use it once again...lol] rubber band does the battery honors, requires a little cardboard shim.
  Otherwise as long as the lead/probe connections stay, they're fine.
  First lead/probe connection to break gets an alligator clip. I like having at least 1 probe on them.
  Just stuff the transistor this way and that {IIRC there's an NPN and a PNP side, each have E/B/C/E...four holes per side, put every which way possible, usually a ballpark hfe# pops up..then you can note pinout, doesn't measure leakage of course, great for quick pinout finding on *most GE's.
Convention creates following, following creates convention.