Rebranded transistors?
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From: Jan Panteltje on 18 Feb 2010 15:44 On a sunny day (Thu, 18 Feb 2010 20:00:58 -0000) it happened "TTman" <someone.pc(a)ntlworld.com> wrote in <70hfn.10439$tJ.10255(a)newsfe28.ams2>: > >"Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message >news:hljk7e$9v$1(a)news.albasani.net... >>I ordered some BC557 from Conrad.nl. >> Normally you can hardly red what is written on a transistor, >> but in this case the label is silver painted masked, >> and does not say 'BC557', but 'B557C': >> ftp://panteltje.com/pub/strange_transistors/BC557_rebranded_img_1806.jpg >> >> Also it looks like the top has been grinded so as to remove any original >> marking. >> I scraped of some of the silver painted text, but I could find nothing >> under it. >> On one of these I thought I could make out the number '2' on the top, >> but then there are people whio see the strangest things in random >> patterns, >> so I am not sure: >> ftp://panteltje.com/pub/strange_transistors/BC557_top_img_1808.jpg >> >> Any body has any idea what the difference is between a BC557 and a C557B? >> Or is it a BC557B? >> Or just any thing painted with the required number? >> >> Other transistors (BC547) look totally normal from Conrad. >> I got a bit supicious when one of these did not work as expected, >> measured the beta, about 330 at low currents, but seems to drop to much >> lower at 100 mA. > >That says to me it's a jap' version and the full part should be 2SB557C. >The Japs always leave off the 2S on small parts. But entering '2SB557C datasheet' into google turns up nop.
From: pimpom on 18 Feb 2010 16:02 Jan Panteltje wrote: > On a sunny day (Thu, 18 Feb 2010 20:00:58 -0000) it happened > "TTman" > <someone.pc(a)ntlworld.com> wrote in > <70hfn.10439$tJ.10255(a)newsfe28.ams2>: > >> >> "Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message >> news:hljk7e$9v$1(a)news.albasani.net... >>> 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? >>> >>> 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. >> >> That says to me it's a jap' version and the full part should >> be >> 2SB557C. The Japs always leave off the 2S on small parts. > > But entering '2SB557C datasheet' into google turns up nop. The 2SB557 was an early PNP power transistor in a TO-3 case. I don't think there was a C sub-type. Certainly not the ones you have.
From: Joerg on 18 Feb 2010 16:06 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? :-) [...] -- SCNR, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Malcolm Moore on 18 Feb 2010 17:17 On Thu, 18 Feb 2010 14:52:25 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> 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? > >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. I've got BC556B in my stock that are maybe ten years old (?) that are labeled exactly the same as yours (same font, same missing B, same thinning of the silver towards the edges), except where yours has W, these have PH, which I understand indicates a Philips device. In 2006 Philips spun off their semiconductors to NXP. Searching the NXP website shows they have discontinued the BC557. Perhaps they sold that line to a company beginning with W. However, http://bos.hack.org/ic_logos/ doesn't list many candidates. I've also got BC327 & BC547 with the same marking style and PH marking. The BC327 was bought about two months ago from a local retail store, BC327 is still listed as current by NXP. I've also got BC640 marked PH (also oldish), some with the silver paint, some with a bluish silver. All have the leading B missing. Regarding the top surface, all the types here are fairly rough on the top, which appears to be merely the moulding process. Using the top surface of TO-92 for alphanumeric labeling is certainly not common. Regards Malcolm. -- Regards Malcolm Remove sharp objects to get a valid e-mail address
From: Jan Panteltje on 18 Feb 2010 18:07
On a sunny day (Fri, 19 Feb 2010 11:17:44 +1300) it happened Malcolm Moore <abor1953needle(a)yahoodagger.co.nz> wrote in <5ncrn552ds5pcicunbvcaqe98tevduoecf(a)4ax.com>: >On Thu, 18 Feb 2010 14:52:25 GMT, Jan Panteltje ><pNaonStpealmtje(a)yahoo.com> 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? >> >>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. > >I've got BC556B in my stock that are maybe ten years old (?) that are >labeled exactly the same as yours (same font, same missing B, same >thinning of the silver towards the edges), except where yours has W, >these have PH, which I understand indicates a Philips device. > >In 2006 Philips spun off their semiconductors to NXP. Searching the >NXP website shows they have discontinued the BC557. Perhaps they sold >that line to a company beginning with W. However, >http://bos.hack.org/ic_logos/ >doesn't list many candidates. > >I've also got BC327 & BC547 with the same marking style and PH >marking. The BC327 was bought about two months ago from a local retail >store, BC327 is still listed as current by NXP. I've also got BC640 >marked PH (also oldish), some with the silver paint, some with a >bluish silver. All have the leading B missing. > >Regarding the top surface, all the types here are fairly rough on the >top, which appears to be merely the moulding process. Using the top >surface of TO-92 for alphanumeric labeling is certainly not common. > >Regards >Malcolm. OK, thank you. Seems it is a 'normal' BC557 then. Some are already in use, hopefully it will keep working :-) |