What does the PN on the PN2222 transistor stands for? - Page 1
Forum section: electronics / beginners

author: Rene
author_rank: Regular Contributor
timestamp: February 13, 2015, 03:44:21 am
content: Hello,Just to satisfy my curiosity, I tried looking up what thePNprefix on thePN2222transistor stands for but was unable to do so. I found all kinds of transistor code standard:Japanese Industrial Standard (JIS)European Electronic Component Manufacturers AssociationJoint Electron Devices Engineering Council (JEDEC)but none of these appear to account for thePNprefix. Does anyone knows what that prefix stands for?Thanks.

author: BlueBill
author_rank: Regular Contributor
timestamp: February 13, 2015, 03:50:47 am
content: Not 100% but I recall it meant Plastic. Where a 2N2222A is a metal can.

author: oPossum
author_rank: Super Contributor
timestamp: February 13, 2015, 03:51:43 am
content: PN2222(A) is the plastic TO-92 package of the metal can TO-18 package 2N2222(A). So P = plastic. Same for the compliment PN2907.Note that some manufacturers still use the 2N2222(A) designation for the plastic TO-92, and the exact specs vary by manufacturer. For example IcMax can be 500 to 1000 mA.The SMT versions are usually MMBT2222(A) and MMBT2907(A).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 13, 2015, 09:36:29 am
content: Digit-letter-number codes have been around since The War or so. Example: 2E26 amplifying tube. I don't remember what all the definitions are (it's seemingly not nearly as consistent as the European definitions, which called out heater, tube type(s) and identifier, e.g. ECC81, ECF80, EL34..), but I believe that's what it's cut from. So "N" comes out to mean "semiconductor device", or something like that. I think the first digit was supposed to be about active electrodes (but that would seem to be broken by the 2E26 having about five inside..), so 1N = diode, 2N = triode (i.e., BJT, FET), 3N = tetrode (dual gate / back gate MOSFET), etc. (some familiar optoisolators got placed in the 4N and 6N ranges, for similar reasons, and so on).AFAIK, those were all kept by JEDEC or whatever.PNxxx wouldn't seem compatible with the pattern, so that may very well be the creation of one company's, which spread by imitation to others.Note that, as JEDEC parts specify everything that they list in the data; there is, strictly speaking, no such thing as a "2N2222 in plastic package"; the metal TO-18 can is as much a core part of the standard as the fact that it's NPN!Of course, you'll never see "SMT 2N7000" (it's TO-92..) requested, because 2N7002 exists (SOT-23).Alas, I've never taken to the MMBT and etc. labels; they're just too damn bulky. I still write "2N3904" on schematics, even when I'm clearly specifying SMTs in the BOM...Tim

author: atferrari
author_rank: Frequent Contributor
timestamp: February 13, 2015, 10:18:39 am
content: The PN prefix is always plastic.From my notes:Japanese2SK2129 - usually 2SK not shown.2SA 2SB PNP2SC 2SD NPN2SF thyristor2SJ 2SK FET / MOSFETKoreanKT is the prefixJEDEC1N diodes2N 3n BJT4N 5 N optocouplersBF (in doubt here) low frequency / audio?BC BD ??

author: retrolefty
author_rank: Super Contributor
timestamp: February 13, 2015, 12:02:40 pm
content: I recall the leading numeric digit indicates the number of terminals of the device, (as in 1Nxxxx, 2Nxxxx) specifies the number of terminals -1, so a 2 lead diode starts with 1, a 3 terminal transistor starts with a 2, etc.

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 13, 2015, 12:28:32 pm
content: Quote from: atferrari on February 13, 2015, 10:18:39 amBC - Low frequency, low powerBD - Low frequency, medium/high powerBF - Medium/high frequency, low powerBL - Medium/high frequency, high powerhttp://en.wikipedia.org/wiki/Pro_Electron