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BC108C

PostPosted: Tue Dec 30, 2014 7:07 am
by David B

Re: BC108C

PostPosted: Tue Dec 30, 2014 8:29 pm
by dai h.
it appears that Motorola manufactured the BC107-109 range:

http://images.ihscontent.net/vipimages/ ... -3-113.pdf

(selector guide 1-23, datasheet: 4-203 in the following Motorola data book from 1984) :

https://archive.org/details/MotorolaSma ... taBook1984

https://en.wikipedia.org/wiki/BC548

(someone's fuzz build using Motorola BC108) :

http://bitterbeard.tumblr.com/post/8606 ... wave-has-a

did you find a cache for cheap?

re: old transistors (if these are from the 90s, they wouldn't be very old at all however), I've read that the gains weren't very high and that made it difficult to design things (not 100% on my thinking, but I thought maybe high gain ones would've been more useful when using feedback to help make circuit operation more consistent. That is, you have the gain you need, plus the extra that can be used for feedback. Maybe a factor when trying to clone originally very old fuzzes?)

Re: BC108C

PostPosted: Wed Dec 31, 2014 9:13 am
by David B
Thanks for the links, yep bumbled into a pile for cheap 8) . Goes without saying gain will need to be measured....
Found this, wondering if Motorola might have had them made by one of several manufactures or did they also produce transistors?

http://datasheetcatalog.com/catalog/p244320.shtml

db

Re: BC108C

PostPosted: Wed Dec 31, 2014 9:19 pm
by dai h.
They seemed to make all sorts of semiconductors, so I would guess they made them. I think I have some individually or inside gear (308 in Rat?, MC33079 quad op amp?, metal body 4558).

The semiconductor part of the business became ON Semi. Apparently Google owns them (not ON Semi but other parts) now:

https://en.wikipedia.org/wiki/Motorola

as far as the specific factory, (from what I vaguely understand) it could be possible that the actual manufacturing could have been done by some subcontractor. From what I've seen Toshiba had some transistors made by S.Korean and Taiwan manfs. "Unisonic" (IIRC) might have been one (Taiwan manf., for gen. purp. types 2SC1815/2SA1015 similar to 2N3904 and 6?).

Re: BC108C

PostPosted: Thu Jan 01, 2015 8:07 am
by David B
Suppose they could have subcontracted them out at some point, also wondering if the K9235 signifies a date & factory code? haven't found anything yet.

Re: BC108C

PostPosted: Thu Jan 01, 2015 9:27 am
by Stu
K = Seoul, Korea; date code is 35th week of 1992.

Re: BC108C

PostPosted: Thu Jan 01, 2015 10:22 am
by David B
Stu wrote:K = Seoul, Korea; date code is 35th week of 1992.


Eureka :!: Thanks Stu.

btw I picked through the devices and found some other branding and flavors, working on pics now...

Re: BC108C

PostPosted: Thu Jan 01, 2015 11:37 am
by David B