While most PN2222s swap C and E compared to 2N2222s, I've come across some PN2222s with the same pin-out as the 2N version. Go figure.
It may also have something to do with the fact that the most common pin-outs on early metal-can transistors match the symbol. Makes it feel natural while designing a TH pcb.
The first plastic-packaged transistors that I saw were essentially TO5 packages, round with the triangular arrangement, epoxy glob-tops. Soon GE was making a thing that looked a lot like a modern TO92, BCE, in a brown epoxy that made the transistors photosensitive.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Most old transistor package types aren't hard to find, but not those for some reason.
NT
Ah, those. They were most commonly available here in India as variants of the BC14x and BC15x series. They were made by Continental Devices India Ltd who named them CIL14x and CIL15x.
Before that the first plastic versions of the popular metal BC1xx series were the unusual six-sided types introduced by, IIRC, Mullard and manufactured by Bharat Electronics Ltd (BEL) in India. I remember making a few of them thinner - for reasons I don't remember - by filing the half-hex side.
Could this be due to the difference between PN2222A (which reportedly has the same pinout as the 2N2222A) and a P2N2222A (which swaps C and E... or, equivalently, turns the TO-92 package around by 180 degrees)?
That seems to be it, except that you got it backwards. It's the P2N2222A that has the same pin-out as the original metal-case
2N2222A. I have the datasheets for both versions. Quite logical too, with the type number standing for "Plastic2N2222A".It's possible that I was wrong about some PN2222As having the same pin-out as a 2N2222A. They might have been P2N2222As. I'll check my stock later and see if the ones with the same pin-out as
2N are indeed P2N.
I cut my teeth on Ferranti e-line transistor rejects from the start of the line where the tinning bath slag had bridged one or more leads. They had a rather nice applications booklet for how to use them too (mine was an earlier white covered version).
That and dead boards from ICL 1900s for 74xx TTL parts. I got quite good at desoldering 14 pin ICs after wrecking a few dozen.
-- Regards, Martin Brown
df
What's actually "wrong" with them is probably one big idiosyncratic custome r, who orders enough parts to get the pin-out and packaging that suits one particular application.
The rest of us just get parts when batches are put through to satisfy that one major customer and their high volume application.
Cambridge Instruments had pretty flexible mounting arrangements for our vis ual displays - regular TV tubes were cheap and good enough for people to lo ok at (the display for generating photographic quality images had a much hi gher quality tube that cost the earth). This meant we never got quite the s ame tube twice, because our batches of a hundred or so were always tacked o n to some different TV manufacturer's order of 100,000 or so, and the tube fitted the TV cabinet that the particular manufacturer thought was fashion able at the time.
-- Bill Sloman, Sydney
As a pre-teen I used to take apart old tube TVs for parts. A transistor or loopstick antenna cost a week's pocket money, so I used 6U8As and 6BA6es to build stuff (that mostly didn't work). ;)
Learned at an early age to keep one hand in my pocket when the power was on. Also the importance of checking bleeder resistor continuity.
Cheers
Phil Hobbs
As a pre-teen I used to take apart old tube TVs for parts. A transistor or loopstick antenna cost a week's pocket money, so I used 6U8As and 6BA6es to build stuff (that mostly didn't work). ;)
Learned at an early age to keep one hand in my pocket when the power was on. Also the importance of checking bleeder resistor continuity.
Cheers
Phil Hobbs
As a pre-teen I used to take apart old tube TVs for parts. A transistor or loopstick antenna cost a week's pocket money, so I used 6U8As and 6BA6es to build stuff (that mostly didn't work). ;)
Learned at an early age to keep one hand in my pocket when the power was on. Also the importance of checking bleeder resistor continuity.
Cheers
Phil Hobbs
As a pre-teen I used to take apart old tube TVs for parts. A transistor or loopstick antenna cost a week's pocket money, so I used 6U8As and 6BA6es to build stuff (that mostly didn't work). ;)
Learned at an early age to keep one hand in my pocket when the power was on. Also the importance of checking bleeder resistor continuity.
Cheers
Phil Hobbs
As a pre-teen I used to take apart old tube TVs for parts. A transistor or loopstick antenna cost a week's pocket money, so I used 6U8As and 6BA6es to build stuff (that mostly didn't work). ;)
Learned at an early age to keep one hand in my pocket when the power was on. Also the importance of checking bleeder resistor continuity.
Cheers
Phil Hobbs
My uncle Sheldon had his own TV repair shop, so I had access to an infinite supply of old tube-type TVs and radios. Plus, he had a shed next to the chicken coop full of old military electronics that he had acquired somehow; knowing Sheldon, he hadn't paid for any of that.
There was lots of WWII surplus for sale then, too, pennies per pound. Tubes, PMTs, flashtubes, oil caps, klystrons, CRTs, radar guts, synchros, indicators, all sorts of wonderful stuff. Apparently someone high up in government decided to dump all that WWII gear on the market for close to free, to encourage brats like me.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Crappy network strikes again!
Cheers
Phil Hobbs (the pool makes up for it)
His nefarious plan appears to have succeded. ;)
Some of that stuff was still around in the '70s. I remember seeing (iirc) A N/ARC-5 transceivers being used with transverters on 20 metres, and I had a T-19 Mk III tank transceiver that didn't work. It had a UHF channel for ta ctical use (330 MHz, I think) that used an E1183 tube with plate and grid c aps, which I'd never seen before.
Cheers
Phil Hobbs
(posting once and then waiting 10 minutes for GG mobile to acknowledge)
Exactly. My father had a basement and an attic full of the stuff from WWII and the Korean war. They gave it away to colleges and universities.
We all feel *so* sorry for you.
Unintended consequences.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Just as I was getting interested in electronics, an Admiral tube plant opened across the road. They would toss all kinds of tubes - 6J6, 6C4,
12AT7, 6AU6, 6AK5 - mainly 7 pin miniatures with some kind of cosmetic defect. I had a field day. I made high gain audio amplifiers and learned about tube microphonics. I bought an old 5" Heathkit scope and this was heaven to see what was going on.This was much better than the old 4 pin triodes from old radios that neighbours donated. I was in tech heaven. Neighbourhood girls that desperately wanted me to screw them stood no chance against a hot soldering iron.
After I got my ham license, I wanted to upgrade from an old 6AG7 with 4 watts on 40 meters to an honest to goodness 6146 transmitting tube. I dug ditches for a week until I got enough money to buy one.
After I put my money down, I opened the carton to inspect it. It slipped out of my hands and went crashing to the floor. Broken glass all over the place.
Another week digging ditches and I got another 6146. Ha. Finally.
I left it in the carton.
Got it home safe and built a nice transmitter around it. While tuning it, I was hunched over the chassis, and a silver cross on a chain around my neck slipped over the front panel and hit the plate. 600V with a couple of microfarads filter cap. I woke up against the wall on the other side of the room, tore off the cross and gave up on religion.
Then along came transistors. I was dismayed to find how easy it was to blow them. This will never last, I said to myself. They are too fragile, forgetting about the number of tubes I had dropped. Of course, I was wrong. After I stopped destroying them, I began to see the benefits. No filament transformer. No 300V B+ to hit you when you not paying attention. No microphonics. Maybe they are useful after all.
Just turned 75. In all, I am extremely grateful for the amazing experiences that electronics brought me.
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