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Post Info TOPIC: ID-ing germaniums
austen


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ID-ing germaniums
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 Hi , great site!


Could anyone help me ID the pinout on this transistor? It's driiving me nuts.


Its an AC187 npn, and there is a painted dot over one lead. Normally I would think that this indicated the emitter, but I think in this case it could be the collector.


I tried to use the GEO method to test for leakage and got some wacky results.


Could HFE be as high as 450 with these?



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austen


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ok more on this....


I am getting possible results in both directions so I used the HFE tester in my multimeter to get an idea- I know not the real gain.


Got HFE of 34 in one direction and 550 in the other Arrrrgh.


I think the DOT must be the collector but 550 is this likely?


Anyone?



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richie


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no



-- Edited by richie on Saturday 10th of April 2010 11:53:09 AM

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mac


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i have some ac187 with a blue dot. this is the collector. the pinout is:
b
e c
bottom view

i gave up on acXXX because all the ones i've measured are very leaky devices, about 700 - 1000uA. Useless.
a quick method to estimate the hFE and leakage is to use a DDM. first plug only the emitter and the collector. then the base. then use RG method to callibrate your ddm.

If possibly try to get some toshiba o matsu****a from the old days. all the ones I have are very consistent and very good sounding despite their characteristics.

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mac
austen


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Thanks.


Well, looks like these are total crap for fuzzes. Darn, I was really excited to find them in an old electronics shop locally.


Huge hfe AND massive leakage. Into the bin!


Think I'll go try the silicon Axis face..



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Col


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I have used some AC187s, the blue dot is the collector. They were leaky but still sounded good and work with my other -ve earth pedals.

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