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Ricko
Joined: Dec 25, 2007
Posts: 251
Location: Sydney, Australia
Audio files: 27
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 Posted: Fri Dec 17, 2010 7:27 am Post subject:
How do you tell the pin out on old transistors? |
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Got around to putting in the last components in the Steiner VCF yesterday: the parts had just arrived from USA after the normal long postal delay.
But then...a mystery. My PN5138 and 2N5172 are not the normal TO-92 packages but are vintage ones: the former looking like water towers and the latter having a kind of skirt. So I am not at all sure of the orientation or even if they have the same pinout as the TO-92 packages which have datasheets. (The pins are in a triangle, not a straight line).
Does anyone know what I should do? (I tried the 5172 in various orientations in the HfE measurement socket on my multimeter, but didn't get anywhere.)
Cheers
Rick |
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RF
Joined: Mar 23, 2007
Posts: 1502
Location: Northern Minnesota, USA
Audio files: 28
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| Posted: Fri Dec 17, 2010 7:57 am Post subject:
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Back in the day... (early 1970's)  If you looked at a transistor from the bottom, oriented the Base of the transistor south, the Emitter was East.
(Base is the one on the bottom of the V shape of the three leads.)
I used that with TO-5, TO-18 and TO-39 packages I think - maybe a few others...
I don't know how universal it is/was - but it worked for me back then.
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www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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dingebre
Joined: Aug 10, 2008
Posts: 270
Location: Salt Lake City, UT USA
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| Posted: Tue Dec 21, 2010 3:26 pm Post subject:
Re: How do you tell the pin out on old transistors? |
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| Ricko wrote: | Got around to putting in the last components in the Steiner VCF yesterday: the parts had just arrived from USA after the normal long postal delay.
But then...a mystery. My PN5138 and 2N5172 are not the normal TO-92 packages but are vintage ones: the former looking like water towers and the latter having a kind of skirt. So I am not at all sure of the orientation or even if they have the same pinout as the TO-92 packages which have datasheets. (The pins are in a triangle, not a straight line).
Does anyone know what I should do? (I tried the 5172 in various orientations in the HfE measurement socket on my multimeter, but didn't get anywhere.)
Cheers
Rick |
The 2N5172 has an BCE pinout (top view, flat away) and will install in the PCB by lining up the flat as indicated on the PCB. If you are using them in the spots labeled for the SSM2210s, you will have to twist the leads to get them installed, use one of the discrete transistor silkscreen as a guide.
For the 2N5138s, Ill double check my stock when I get home, but looking at the top of the transistor with the base of the triangle away from you, the pin on the left is the emitter, middle base, right collector. (I had it backwards earlier...)
see attached photo and this page on the website:
http://www.xmission.com/~dingebre/Transistor_photos.html
This is one of an old 2N5138 which I bought in 1974.
I'll try to post a couple of photos tonight.
David
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_________________
David M. Ingebretsen, M.S., M.E.
Collision Forensics & Enginering, Inc.
dingebre@3dphysics.net
http://www.xmission.com/~dingebre/Synthasystem.html |
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Ricko
Joined: Dec 25, 2007
Posts: 251
Location: Sydney, Australia
Audio files: 27
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| Posted: Wed Dec 22, 2010 6:58 am Post subject:
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Brilliant! Thanks so much for that
Rick |
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RF
Joined: Mar 23, 2007
Posts: 1502
Location: Northern Minnesota, USA
Audio files: 28
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| Posted: Wed Dec 22, 2010 7:43 am Post subject:
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...base is south...emitter is east. Go figure 
_________________
www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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