Rebranded transistors?
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From: krw on 20 Feb 2010 00:50 On Thu, 18 Feb 2010 15:59:17 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Thu, 18 Feb 2010 21:16:06 +0530) it happened "pimpom" ><pimpom(a)invalid.invalid> wrote in <hljnc5$5pm$1(a)news.albasani.net>: > >>Jan Panteltje wrote: >>> I ordered some BC557 from Conrad.nl. >>> Normally you can hardly red what is written on a transistor, >>> but in this case the label is silver painted masked, >>> and does not say 'BC557', but 'B557C': >>> ftp://panteltje.com/pub/strange_transistors/BC557_rebranded_img_1806.jpg >>> >>> Also it looks like the top has been grinded so as to remove any >>> original marking. >>> I scraped of some of the silver painted text, but I could find >>> nothing under it. >>> On one of these I thought I could make out the number '2' on >>> the top, >>> but then there are people whio see the strangest things in >>> random >>> patterns, >>> so I am not sure: >>> ftp://panteltje.com/pub/strange_transistors/BC557_top_img_1808.jpg >>> >>> Any body has any idea what the difference is between a BC557 >>> and a >>> C557B? >>> Or is it a BC557B? >>> Or just any thing painted with the required number? >>> >> >>I've occasionally had batches of BC547s and BC557s marked just as >>in the first picture, printed on the silvered front face of a >>TO92 case with the leading 'B' omitted. I didn't measure the beta >>carefully but never encountered any unexpected results on using >>them. As for the missing B, I assumed that some manufacturers >>were following the Japanese practice of omitting the leading '2S' >>from their type numbers, presumably to enable using reasonably >>large characters on a limited surface area. > >OK, but then why grind of the top? > > >>I remember saying to a friend when I first came across such >>markings on European type transistors, "Oh oh, this could lead to >>some confusion. There may be times when we can't be sure if it's >>BCxxx or 2SCxxx." > >Yes, numbers should be the way they are. > > >> >>> Other transistors (BC547) look totally normal from Conrad. >>> I got a bit supicious when one of these did not work as >>> expected, >>> measured the beta, about 330 at low currents, but seems to drop >>> to >>> much lower at 100 mA. >> >>The beta vs. Ic curve on Philips' datasheet for a typical BC557B >>gives beta of ~320 at 1mA and ~170 at 100mA. I don't find this >>surprising as 100mA _is_ the maximum continuous Ic rating, and >>it's quite normal for Si transistors to show considerable drops >>in beta as we approach max Ic. > >Maybe these are genuine, but I would prefer a label like 'Philips' or 'Motorola' or whatever. >Why hide the manufacturer? You don't think a fraudster would rip off a trademark? >Or does 'W' stand for some company? alorotoM? >Maybe someone in China is just spray-painting a lot of universal PNPs :-) >And you also had some of those :-)
From: Joerg on 21 Feb 2010 18:40 Michael A. Terrell wrote: > Joerg wrote: >> Jan Panteltje wrote: >>> On a sunny day (Thu, 18 Feb 2010 21:16:06 +0530) it happened "pimpom" >>> <pimpom(a)invalid.invalid> wrote in <hljnc5$5pm$1(a)news.albasani.net>: >>> >> [...] >> >>>> The beta vs. Ic curve on Philips' datasheet for a typical BC557B >>>> gives beta of ~320 at 1mA and ~170 at 100mA. I don't find this >>>> surprising as 100mA _is_ the maximum continuous Ic rating, and >>>> it's quite normal for Si transistors to show considerable drops >>>> in beta as we approach max Ic. >> Yep, doesn't sound unusual. >> >>> Maybe these are genuine, but I would prefer a label like 'Philips' or 'Motorola' or whatever. >>> Why hide the manufacturer? >>> Or does 'W' stand for some company? >>> >> Wilips? Wotorola? Uncle Wen's Wonder Works? > > > At one time it was used by Workman Electronics for their replacement > line of semiconductors at a time when dozens of small companies hoped to > replace the Sylvania - ECG line as the top seller. > But this was probably in the days of Ge-transistor, the Beetles, duck and cover, long hair and Hippie buses :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Michael A. Terrell on 21 Feb 2010 23:49
Joerg wrote: > > Michael A. Terrell wrote: > > Joerg wrote: > >> Jan Panteltje wrote: > >>> On a sunny day (Thu, 18 Feb 2010 21:16:06 +0530) it happened "pimpom" > >>> <pimpom(a)invalid.invalid> wrote in <hljnc5$5pm$1(a)news.albasani.net>: > >>> > >> [...] > >> > >>>> The beta vs. Ic curve on Philips' datasheet for a typical BC557B > >>>> gives beta of ~320 at 1mA and ~170 at 100mA. I don't find this > >>>> surprising as 100mA _is_ the maximum continuous Ic rating, and > >>>> it's quite normal for Si transistors to show considerable drops > >>>> in beta as we approach max Ic. > >> Yep, doesn't sound unusual. > >> > >>> Maybe these are genuine, but I would prefer a label like 'Philips' or 'Motorola' or whatever. > >>> Why hide the manufacturer? > >>> Or does 'W' stand for some company? > >>> > >> Wilips? Wotorola? Uncle Wen's Wonder Works? > > > > > > At one time it was used by Workman Electronics for their replacement > > line of semiconductors at a time when dozens of small companies hoped to > > replace the Sylvania - ECG line as the top seller. > > > > But this was probably in the days of Ge-transistor, the Beetles, duck > and cover, long hair and Hippie buses :-) No, the US had silicon transistors by then. -- Greed is the root of all eBay. |