Japanese Transistors and identification?

[Diabolical Artificer]

This site is brilliant for finding equivalents - https://alltransistors.com also to find an equivalent device just google "2SC**** equivalent"

Andy.

[Malcolm T]

Right, so i,ve got this heap of unmarked / poorly marked devices with three legs in black plastic encapsulation that i want to identify for small projects, i dont want to go sticking volts up the legs as the junctions will / might be damaged , i,m pretty certain there are trannies and fets in the bunch. Whats the safest way of probing around then. Its easy with a trannie but a FET ?. I will try and take some piccies later on .

[paulsherwin]

Buy one of the cheap component analyser boards available from Chinese eBay sellers for under £10. Many of us here use them. They will quickly identify a device and tell you what the leadout is.

Most basic digital multimeters have a transistor hfe tester built in. You can use these to identify NPN/PNP transistors and their leadouts, but it's more fiddly than using a component analyser as you need to try the component in all the possible orientations until you get a sensible reading.

[Malcolm T]

Right thanks for the tips and help, more sorting out to do LOL.

[Jolly 7]

I own one of the cheaper component testers but one of its limitations is its inability to accommodate MOSFETs for testing. I wonder if any relatively cheap tester can also test four-pin devices such as MOSFETs or bridge rectifiers?

[paulsherwin]

Yes, all the cheap ones I know of only handle 2 and 3 lead devices.

[Malcolm T]

My cheapie i have is this
https://www.snapdeal.com/product/kro...30d/1436635049

Works for me BJT test only but not for FET,s

[paulsherwin]

That is the very well known DT830 meter churned out in enormous quantities. I have several of them. They are incredibly cheap and nasty, but are reasonably accurate and adequate for low voltage work. The hfe test works well enough if the transistor socket contacts are OK. As you say, it won't test FETs, but anything that doesn't test sensibly as a transistor is most likely to be an FET.

One thing to bear in mind is that general purpose Si transistors are very cheap - £1 for 50 from Chinese eBay sellers - so it may not be worth spending lots of time and money trying to identify unmarked types.

[Malcolm T]

It was dirt cheap so thought i,d give it a go, it has proved useful though .
In your opinion whats the reliability of the Chinese gear then or is it a jamboree bag dip !
I,ve seen some whacky high prices on ebay for 2N3819 etcetc almost insulting .
I suppose surface mount would be a cheaper option but then its a different ball game that one but then i will have a go at anything , never too old to learn !.

[paulsherwin]

I've never had problems ordering cheap transistors like 2N3904s from China as there's no point in faking them at that price point. You have to be careful with specialist components that are much cheaper than they ought to be though.

2N3819s are pretty cheap, though more expensive than jellybean bipolars.

[Malcolm T]

Hmmm might be worth a try, thanks .

[Argus25]

Originally Posted by Diabolical Artificer

This site is brilliant for finding equivalents - https://alltransistors.com also to find an equivalent device just google "2SC**** equivalent"

Andy.

It failed the first test I gave it.

The better source are the VRT Manuals, Vol 1 & 2. These are by Tech publications PTE Ltd in Singapore, which are the Asia Pacific versions. They originate from ECA Electronic & Acoustic GmbH, Germany.

These have practically every transistor letter or number prefix specs with suggested equivalents going right back to the earliest version made by each manufacturer.

Just to give one example, the website you cited doesn't know that the 2SA358 is the equivalent of the AF118 and the specs it lists for the 2SA358 are incorrect with a misquoted ft. But its all there in the VRT manuals.

[ajgriff]

I have found the site recommended by Andy a very useful indicator in the past but it's always important to check actual data sheets (usually possible on-line) to verify that a device is suitable for a particular application.

The trouble with the VRT manuals is that they are not readily available in the UK and are relatively expensive for amateurs like me. My 50p car boot copy of Towers is extremely useful.

Alan

[Argus25]

Originally Posted by ajgriff

...but it's always important to check actual data sheets (usually possible on-line) to verify that a device is suitable for a particular application.

My 50p car boot copy of Towers is extremely useful.

Alan

Once a semiconductor faking company got caught out by Towers. There is an error that list a Jfet as a BJT in one of the editions. So when they faked the part, they sent the customer (me) NPN silicon transistors instead of Jfets. So you are right, always double check everything with the motto detectives use: "Assume nothing, trust nobody and check everything"

[emeritus]

The wrong entry might have been unintentional, but it is not unknown for publishers of directories and street maps to intentionally include incorrect entries to prove unauthorized copying.

[julie_m]

Just imagine if they had done that with a book of mathematical tables, and some hapless engineer had relied upon a value that -- unbeknownst to them -- was a deliberate error, inserted for the purpose of catching plagiarists, in the design of a bridge that subsequently collapsed .....

[TonyDuell]

Originally Posted by emeritus

The wrong entry might have been unintentional, but it is not unknown for publishers of directories and street maps to intentionally include incorrect entries to prove unauthorized copying.

I would hope that no databook would ever deliberately include incorrect information on an existing device. After all it's possible that somebody would be using said device.

I think it's more likely that Towers would include information on a transistor that had never existed. Nobody could genuinely have been using that, but if anyone copied the book it would show up.

['LIVEWIRE?']

That DMM appears to be the same as the M-830B, one of which I have, which is, as Malcolm says, useful for low-voltage work, and testing Bipolar Transistors. My M-300 DMM also has the facility to test Bipolars & maybe UJTs, but not FETs. Somewhere I still have an AVO TT169, which, IIRC, does test all types of semiconductor made at the time the 169 was in production.

[Malcolm T]

Ok fellas, aside from RS CPC and Farnell what shops are there in UK that can supply components at what i call reasonable costs , or very cheap, other than the chinese which i am looking at , like we used to have years ago ( not Maplins ) in the 60s and 70s and 80s.
I dont want to pay silly prices. Any names anyone ?. Even NOS considered or Ex stock.

['LIVEWIRE?']

There is, or was a shop in Cheltenham (Hardings, IIRC) which sold all sorts of electronic components. Googling them should find their contact details. Cricklewood Electronics have a shop in Cricklewood, London, but I know of no others with retail Outlets. On the web, Cricklewood, Rapid Electronics, and Vintage Parts.com (url is something like 'markhindeseasywebstore.com, but needs confirmation.)