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Old 12-15-2013, 05:08 PM
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wa2ise wa2ise is offline
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Join Date: Dec 2002
Location: USA
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Source of Germanium transistors, old Ma Bell touchtone phone

Looks like that transistor used in the old touch tone keypads is Germanium. It measures around 0.25V BE and BC junctions with my DVM in diode mode. Though mine dated back to 1974, that should still be Germanium. It's PNP.



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I was a wrong number at the phone company...
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File Type: jpg touchtonepadgetransistor.jpg (29.2 KB, 128 views)
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