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Old 21st December 2005, 06:21 PM   #1
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Default counterfeit or clone?

I've got some 2SA1302 and 2SC3281 transistors that I ordered from RS components in the UK. Having read a lot about counterfeit devices on this forum, I've been left wondering if the devices I have are clones (they are not marked Toshiba, but with three 45 degree arrows pointing up and left) or counterfeits.

So I set up the attached test circuit, with digital voltmeters to read the voltage across R1 and R2, and an oscilloscope to observe Vce of the transistor to ensure it was set to 5 V. V1 and V2 were supplied from my lovely TTi CPX400A bench power supply.

I tested the device up to an Ic of 6.5 A, and it worked just fine (results attached to next post)

Do you think these are genuine devices? If not, why not? Would you run any more tests? Would you bother testing the 2SA1302 devices as well?

Anyone know who makes these devices?
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Old 21st December 2005, 06:23 PM   #2
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Default test results

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Old 21st December 2005, 07:07 PM   #3
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Toshiba endorsed versions are made in a Toshiba owned factory in Korea, marked as KSA and KSC types.
WingShing in China makes these numbers too , but those are not the same as the originals.
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Old 22nd December 2005, 12:43 AM   #4
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You may need to check the printing on the transistors.
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Old 22nd December 2005, 01:02 AM   #5
jaycee is offline jaycee  United Kingdom
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The logo you have described is the Semelab logo

www.semelab.co.uk

I don't know how they compare to the Toshiba devices but they are legit.
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Old 22nd December 2005, 10:06 AM   #6
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Magnatec is the producer, legit may be a strange word.
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Old 22nd December 2005, 10:08 AM   #7
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http://www.diyaudio.com/forums/showt...120#post518120
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Old 22nd December 2005, 11:43 AM   #8
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Thanks everyone for your responses.

jacco, Magnatec is a distributer, not a manufacturer. It is possible that they sold counterfeits in the past, but now sell clones.

The transistors I have have the same logo as the transistor second on the right in the picture of the second post in the thread that you linked. However, the printing and general construction is of a much higher standard. I will post a picture later today.

I did another quick and dirty test last night, testing the beta at high frequency (1 MHz) and medium current (around 0.8 A rms). Unfortunately, I didn't have anything to hand to accurately measure the ac base current, but the gain seemed to be pretty close to what you would expect for an Ft of 30 MHz.

I'm surprised no-one's commented on the results of the first test I performed. They seem to suggest the device is behaving according to the data sheet do they not? The only thing I know for sure is that these devices were not made by Toshiba. Do semelab have the rights to produce this transistor? Or did they just develop their own with the same characteristics and then give it the same part number?

What's the easiest way to crack open the package so that I can see the die? (I have a spare that I don't mind sacrificing, I'll probably test it close to the official 2SC3281 SOA first to see if it survives).
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Old 22nd December 2005, 12:08 PM   #9
johnnyx is offline johnnyx  United Kingdom
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I don't think you should worry about it. RS is a good reputable supplier, ISO9000 quality systems and all. Second sourcing is a good thing; product manufacturers are not tied to one source of components, so if anything should go wrong with a batch, there is an alternative supply. I know that things can go wrong. The competition can help to reduce prices too. It seems to measure ok, so it is ok.
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Old 22nd December 2005, 12:17 PM   #10
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hi johnny, thanks for your response.

I suppose I'm not doing this just for myself, but for the re-assurance of others too. Both RS and Farnell have been stung by the counterfeit problem in the past, and there are a few posts on this forum stating that ALL new 2SA1302 and 2SC3281 are counterfeit because they are no longer produced. It seems to me that this is not true, there are third parties who now manufacture legitimate devices. If I can supply enough credible information to demonstrate that these are 'proper' devices, that could help others make informed decisions.
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