Identify manufactor for simple 2n2222a - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: September 06, 2021, 06:18:35 pm
content: TL;DR - how do you tell which manufacturer made a TO-92 NPN?A long time ago I had a bunch of basic jelly bean BJT transistors delivered as I was getting into my "new" hobby. The problem is that the datasheet I've been using from ONSEMI (https://www.onsemi.com/pdf/datasheet/p2n2222a-d.pdf) doesn't correspond to what I see on these units. And since I rarely use these guys (I wish I'd known back then - got a whole bunch of them) I seem to make the same mistake of thinking the datasheet I have is correct, and the results of course are predictable.This is a close up of the transistor. The markings are: 2N 2222A H 331And I'm clueless on how I determine WHO made these so I can find the RIGHT datasheet next time.As my tester shows, the ONSEMI datasheet has the Emitter and Collector switched around. The datasheet says Collector is pin 1, but tests and usage tells me it's pin 3. So my conclusion is simple - I have the wrong datasheet. I just don't know how to tell WHICH one.I'm well aware these may be no-name Chinese brands which is why I could get a lot of them for no money 5+ years ago. Since I rarely use them, I may just print a small pin-out and put it in the drawer with them so next time I don't make the mistake. But I'm curious - how can you tell?

author: RoGeorge
author_rank: Super Contributor
timestamp: September 06, 2021, 06:46:35 pm
content: I'll trust the datasheet, the multitester might mistake.If in doubt, use a very high resistance (100k ... 1Mohm) series with a voltage source of at least 10V DC, and in series with the base. Reverse polarize each junction, one at a time. On the BE reverse polarized there should be about 6-7V or so (the BE breakdown/Zenner voltage), on the BC reverse polarized should be more, upto 40V if the DC source is that much. Whichever measures more when reverse polarized, that is the BC junction.My multitester has different pinout on each side of the socket.What is it written above the ZIF socket, on the other side, still 1, 2, 3?

author: magic
author_rank: Super Contributor
timestamp: September 06, 2021, 06:48:15 pm
content: P2N2222 is a weird animal with CBE pinout like on BC54x/55x transistors.AFAIK all other 2N2222 and PN2222 in TO-92 case use the EBC pinout. I'm sure that ON also makes some 2N2222 or PN2222 with the usual pinout and you could find the datasheet for that. They may even have two datasheets: one for their original (ex-Motorola) part and the newer one they acquired with Fairchild Semiconductor.editThese don't look like Chinesium if they have some lot code printed on them. Bottom of the barrel vendors don't bother with that and only print the part number. I guess it saves them a fraction of a penny.

author: gamalot
author_rank: Super Contributor
timestamp: September 06, 2021, 06:55:48 pm
content: The pinout sequence of P2N2222A and 2N2222A (or PN2222A) is different, it has nothing to do with whether it is a Chinese brand or not.

author: bdunham7
author_rank: Super Contributor
timestamp: September 06, 2021, 07:05:14 pm
content: Quote from: RoGeorge on September 06, 2021, 06:46:35 pmAny decent version of the Mega328 component tester is very unlikely to make a mistake like that. In fact, the datasheet is more likely to be wrong, which in this case it was. Identifying mystery meat components can be a bit trickier and these testers can't spot everything, but if I put a known J-Fet or NPN transistor in and it tells me it is a capacitor, my first thought is not "oh that cheap POS is probably wrong".

author: magic
author_rank: Super Contributor
timestamp: September 06, 2021, 07:07:06 pm
content: Quote from: RoGeorge on September 06, 2021, 06:46:35 pmThis is not really necessary and risks damaging the transistor. More obvious difference is beta - much lower in the wrong direction. It's so simple that those testers should get it right.

author: TimFox
author_rank: Super Contributor
timestamp: September 06, 2021, 07:40:59 pm
content: Note that the “2N2222” and “2N2222A” , as registered with JEDEC, are TO-18 metal case devices. The same chip in plastic is sold as “PN2222” and other prefixes, with different pinouts. Manufacturers that use the “2N” prefix with plastic 2222’s confuse the issue. The 2N3904, on the other hand, is an example of a transistor that has always been in a TO-92 plastic package. There are other prefixes for both chips that are in surface-mount packages.As an old fogey, I prefer the original triangular pinout of the TO-18, since it makes terminal identification easier.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 06, 2021, 09:29:28 pm
content: I have a big assortment of TO-92 BJTs that are all marked "331" and I couldn't find the manufacturer either, some Chinese mystery plant I guess.Any TO-92 2222 datasheet should be close enough aside from the pinout.

author: gcewing
author_rank: Regular Contributor
timestamp: September 07, 2021, 12:19:31 pm
content: Confusion abounds indeed...This page has a picture of a 2N2222A with the same H331 marking as yours, and a pinout diagram that agrees with what your component tester says.https://components101.com/transistors/2n2222a-pinout-equivalent-datasheetBut then they go and link to a datasheet for the P2N2222A with the reversed pinout...