Rebranded transistors?

marking.

at 100 mA.

John

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.

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."

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.

On a sunny day (Thu, 18 Feb 2010 21:16:06 +0530) it happened "pimpom" wrote in :

OK, but then why grind of the top?

Yes, numbers should be the way they are.

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?

Maybe someone in China is just spray-painting a lot of universal PNPs :-) And you also had some of those :-)

On a sunny day (Thu, 18 Feb 2010 07:30:10 -0800) it happened John Larkin wrote in :

marking.

it.

at 100 mA.

Thank you John, that article sure makes one wonder.

Sadly, it's true. Though, as I wrote in my reply to Jan's post, I've used many transistors marked as in his picture without observing any difference in performance.

Even in India, Delhi, the nation's capital, is known as the capital of counterfeit products (counterfeits are called 'duplicates' in Indian English). It's why I avoid buying from Delhi-based shops and companies.

This is not just in electronic components, but also in most other areas. A friend who owns a car repair shop once told me that they have a choice of several grades of counterfeit called D1, D2, D3 etc. The D' stands for 'duplicate', with D1 being the highest grade!!

A strong possibility. Maybe omitting the 'B' is an attempt to avoid legal issues rather than to increase character size: "We never sold this as a BCxxx"

Years ago (IIRC ~2002) I bought a batch of BC54x and BC55x from a renowned distributor, so hopefully this should guarantee that they were the original stuff. Those looked exactly as the one in your image. I'm not sure though, who manaufactured them, possibly Motorola or Philips. Judging from this I tend to say that these are not rebranded, but perhaps old transistors.

I can't see on the image whether they are grinded or just cheapish molded.

at 100 mA.

Seems quite normal to me for B-grade BC557.

Of course these days, you can't be absolutely sure, but they are probably OK.

Hth Klaus

On a sunny day (Thu, 18 Feb 2010 18:53:14 +0100) it happened Klaus Bahner wrote in :

I tried to take a picture of the top that showed that, but you can only see it in some light. So that picture is not very clear. But you can, with a magnifying gllas, clearly see the traces of the grinding tool :-).

at 100 mA.

So far I have used a few, normal things work. Some application that pushed it a bit needed modification... Could be my circuit too :-)

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.

On a sunny day (Thu, 18 Feb 2010 20:00:58 -0000) it happened "TTman" wrote in :

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.

Yep, doesn't sound unusual.

'Motorola' or whatever.

Wilips? Wotorola? Uncle Wen's Wonder Works?

:-)

marking.

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,

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

On a sunny day (Fri, 19 Feb 2010 11:17:44 +1300) it happened Malcolm Moore wrote in :

marking.

it.

at 100 mA.

OK, thank you. Seems it is a 'normal' BC557 then. Some are already in use, hopefully it will keep working :-)

marking.

nder it.

ns,

lower at 100 mA.

seem like a lot of trouble to go through to fake something that cost a few cents if you buy it from digikey

-Lasse

marking.

it.

at 100 mA.

I've seen pictures of counterfeit capacitors that consist of the casing of say, a 200V 660uF capacitor, but inside is just empty space and a

"Jan Panteltje"

The "C" very likely stands for Conrad.

Makers will apply any number the buyer asks for.

.... Phil

Considering the time and effort spent I don't know how that could be very profitable.

I guess if a major manufacturer did it they would make some coin or if you labour force worked for a nickel an hour in some sweat shop.

Nothing really suprises me anymore.

"Hammy"

The shrink plastic label on the oversize can indicates a top brad name like Nippon Chemi-con or Sprague.

What is inside is a small, no brand POS extracted from used equipment like old CFLs.

Means converting worthless junk into cash using child labour in China or India.

.... Phil