{"id":6842,"date":"2013-03-25T16:08:59","date_gmt":"2013-03-25T23:08:59","guid":{"rendered":"http:\/\/rustybolt.info\/wordpress\/?p=6842"},"modified":"2013-04-02T06:51:07","modified_gmt":"2013-04-02T13:51:07","slug":"2013-03-25-tbd","status":"publish","type":"post","link":"https:\/\/rustybolt.info\/wordpress\/?p=6842","title":{"rendered":"2013-03-25 Germanium Transistor Guts"},"content":{"rendered":"

\"P1030353S2\"<\/a>I took this picture by holding a two lens pocket magnifier in front of my point-n-shoot camera.\u00a0 I came out good considering that the magnifying lenses had no color correction.\u00a0 That’s why there’s a slight color fringe at some dark and light points.<\/p>\n

This is an old germanium transistor from the late ’50s or early ’60s made by Texas Instruments.\u00a0 I filed off the edge around the case and pulled the cap off.\u00a0 The diameter of the whole disk is about 1\/8″ or 3mm, which is huge by today’s standards.\u00a0 Today they could get a whole microprocessor in that size disk.\u00a0 The actual transistor chip is the inner disk, and this disk itself is the base of the transistor.\u00a0 The bond wire from the ‘post’ comes over and goes into the blob in the center of\u00a0 the disk, which is the collector.\u00a0 The other side has one that looks almost the same, but it is the emitter.<\/p>\n

Germanium has to be put into a hermetically sealed package because the germanium cannot be passivated like silicon.\u00a0 Silicon can be passivated by changing the surface to silicon dioxide, or glass.\u00a0 Then epoxy or plastic can be put over the silicon chip.\u00a0 The first germanium transistors were packaged in plastic, but they went bad as the moisture in the air seeped up through the space between the plastic and the wire leads.\u00a0 The manufacturers then changed to a hermetically sealed metal package.\u00a0 In this case, the metal base, shaped like an upside down pan, is filled with glass, which seals the leads where they go through the glass.\u00a0 Nothing could get through the case once the lid was welded on.\u00a0 I removed this cap years ago, so the chip has been exposed to moisture and air and has most likely quit working shortly after it was removed.<\/p>\n","protected":false},"excerpt":{"rendered":"

I took this picture by holding a two lens pocket magnifier in front of my point-n-shoot camera.\u00a0 I came out good considering that the magnifying lenses had no color correction.\u00a0 That’s why there’s a slight color fringe at some dark and light points. This is an old germanium transistor from the late ’50s or early <\/p>\n

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