Help: OC140 pin out question.

[rlopes]

Hello.
Some time ago i found some some OC140 transistors in a local shop. They seem to be made of black glass, with the word "OC140" and below that the letters "VWY" both words in white and they have a red dot near one of the transtistor legs.
At radiomuseum.org they say OC140 are "made by Valvo - Germany (...) NPN germanium junction transistor Intended the switch and / or bi-directional applications. All-glass body, blue (?) Indicates dot collector. Also made by Philips and related manufacturing plants".

I tested them with my PEAK Atlas DCA55 and i've got diferent pin out readings according to their gain.
The transistors with lower gains (Hfe =54, 55, 58, 62, 68), the pin out would be the expected: Red Dot = Collector -> B -> E.
The transistors with higher gains (Hfe = 96, 126, 160 and 162) the pin out is inverted so Red Dot = Emiter -> B -> C.
Does anyone experienced this or does anyone knows why this happens? And what is the real OC140 pin out?
Best Regards

[Mike B.]

The red dot has been the collector on almost any Germanium I've ever seen. I'm not sure why the DCA55 is reading the reverse for the others. Perhaps something is not right with those?

[rlopes]

I don't know if there's something wrong with them but i did test them in a treble boost circuit and they sounded good to my ears. But i want to be sure about the transistor pin out because, at least with this circuit, they worked in any of the 2 positions but soundwise they were a little different.

[Soup39]

red dot is collector based on this handy reference:

http://www.beavisaudio.com/techpages/Transistor-Pinouts/index.htm#oc

[Rockhorst]

OC139, OC140 and OC141 are sort of symmetric: they can work both ways. I've had a bunch of OC139 transistors that had higher gains when used reversed.

[rlopes]

Could this be a mistake when they label them? Could the red dot be misplaced because of some factory error? The curious is that all the transistors with less gain have the expected pin out and the ones with higher gain have it reversed. I think i'm going to try them again in both positions and i will use the one i like the most because as i said the sound is a little different.

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