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Obsolete Parts

Not so much here (on Usenet (or more properly, the Google Groups Convenient Interface To Usenet)), but at times in electronics related IRC Channels, I hear periodic scoffing at various parts I'm using or have inventory of. Namely, things like the LM741, the 2N2222, maybe the TTL555, vacuum tubes and other 'old school' stuff that's been easily outdone several times over with replacements that are more reliable, more efficient, less noisy, cheaper, and all-round better in every way.

True, there's a certain amount of silliness among some audiophiles and musicians (especially guitarists) when it comes to 'old equipment' (and I only say this because I'm guilty of it too), but I would expect this audience to be very fractional. (In a nutshell, guitar effects are often about polluting the otherwise good signal with *crap*, and other artifacts that result from the limitations of the devices or circuit).

So why do they still make the 741, or the 2N2222? Or some of those old opamps that can latch up tight with the right or wrong input signal, never to return till the power is cut off? Are there still uses for these old designs that newer components won't accommodate?

What's keeping them alive?

:-)

Reply to
phaeton
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1/ Low cost 2/ Habits (older designers still turning a trick or two) 3/ Many suppliers 4/ A plethora of application data and neat circuits 5/ A form factor allowing experimentation ... one can hand-solder to them
Reply to
Charles

Because ppl still buy them. That's the only reason ever.

For some unchallenging applications a cheap 741 is doubtless quite fine although I'd expect it to be deprecated by now if only for unsatisfactory single-rail operation and high quiescent current consumption by modern standards.

As for the 2N2222 do you mean the PN2222 ? The 2N2222 is in metal can (TO-18) and very expensive as a result.

The PN2222 is in TO-92 and is just a general purpose npn silicon transsitor with fairly average specs. At least it's not pricey but more modern devices typically have loads more current gain which is usually a desirable parameter.

I've never seen/noticed the 2222 suggested in European hobby sources byw.

Graham

Reply to
Eeyore

That's because they have always used the BC families. I think a suitable replacement for the PN2222a is the BC547b.

Someone will correct me if this number is wrong. :-)

However, you must swing the pinout 180 degrees for them to work. And yes, they still make mountains of the BC equivalent.

Don...

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Reply to
Don McKenzie

Pretty much. The 2N3904 etc family was popular once too for hobby stuff as were some of the Motorola 'house' devices.

No, you got it right. The BC546/7/8/9/550 family do have lots more current gain though. Higher current gain seems to be associated with more modern devices.

The pinout will be the same as a 2N2222. Most of the BCs have the same pinout as TO-18.

And even the Chinese use them.

Graham

Reply to
Eeyore

In that case, they must be making zillions of them Graham. (No doubt with the OEM markings still on them.) :-)

Don...

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Reply to
Don McKenzie

Our supplier used Philips parts for the BC5xx's. They're so multi-sourced I doubt anyone needs to market any 'dodgy' ones.

Graham

Reply to
Eeyore

although

with

typically

Actually Graham, I do mean the metal can 2N2222. I have about 20 of them on hand, and I frequently run into* circuits on the intarweb that spec them. I've also got tons of BC stuff, mostly from a Futurlec transistor assortment. These aren't spec'd so often, but I sometimes substitute them on the breadboard and they usually do fine. As I (might have) said before, I mainly do music-related audio stuff which is in the strange category of intentionally adding noise and disgruntlement to a perfectly good signal.

-phaeton

(*) "frequently run into circuits"....... this is another discussion entirely (but wtf, i'm game), but I seem to notice that there is an MFT** of electronics tutorials, data sheets, and other info available on the web. Seems however, that probably 90% of it resides on pages that still say "last updated mm/dd/1997" or so. I don't know what happened in 1997, but this invaluable resource dried up about that time, leaving behind only relics that will someday die. Sad.

(**) MFT == Metric FuckTon

Reply to
phaeton

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