What's the LM324 of the day?

But only because you didn't have Dachshunds then. Whenever I do some PWM stuff in the lab and it gets below 30kHz the Shepard gives me the looks and leaves. The Rottweiler snores right through it.

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Regards, Joerg

http://www.analogconsultants.com/

Current regulated? Or just voltage regulated and using the big chokes as a ballast? Sine wave output or square wave? Relaxation oscillator or known, fixed frequency?

Just curious as I keep meaning to build something like that myself some day...

I've read Jim Williams' old app note on driving CCFLs, and he's a big proponent of current regulation since wave output inverters.

---Joel

I had a 1950 Nash with a vibrator pack "switcher". The choke was the magnet coil for the speaker ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave

I don't remember much. I was a kid back then and although I did always try to create proper documentation this one was different. It drove me crazy that those lamps (it was in Europe) started with this long flicker and I whipped it all up in a hurry, never looked back once it worked. So I built a free running oscillator, two big old TV transistors drove a pulse transformer that I made from the laminated core of a small tube audio transformer. Number of store-bought new parts: Zilch.

Current regulated? Absolutamente not, AFAIR this thing was not regulated at all. The oscillator was a simple multivibrator. It all hung directly on 230VAC mains. IIRC the transistors were rated 400V (some kind of AD2xx types) so it's a miracle that this thing lasted forever.

Well, yeah, but I was a teenager back then. Not a worry in the sky. The amazing thing: These now happened to be the only fluorescent lamps in the house that would never burn out. So I must have done something right, I just don't remember what :-)

--
Regards, Joerg

http://www.analogconsultants.com/

Thanks for the details, Joerg.

I remember being in elementary school and discovering by trial and error why the switch of these fluorescent desk lamps had three positions (off, on, and "warm the filaments"). I was lead astray for awhile, since I found that if you very rapidly flipped the things on-off-on, they'd light (I guess it generated enough of a spike to ionize the gas...) and I figured they were all just a little flaky, only discovering a little later that the appropriate "turn on" sequence was warm->on. :-)

Oh yeah, understood. Jim's talking about designs for laptop LCD backlights, where obviously everything matters a little more.

---Joel

^^^ The point of this bit of nostalgia being that I then came to prefer lights with off/on/warm over those with built-in starters and the flickering that you mention!

That was just the trick with this switcher. It no longer needed a pre-warm. In fact the fluorescents in there were discards (a.k.a. "free") with broken filaments. They lit just fine.

Well, after something worked pretty much immediately people can exhibit quite an ego. So did I: Built a shortwave power amp that could deliver a staunch 1500 watts of RF output power. It was legal because the top ham radio license class over there limited the plate dissipation and someone had found an official data sheet of 30W per tube. So we were allowed five.

This amp also worked instantly. However, I was blissfully unaware that capacitors have an ESR and ripple current limits. WHADDABAM! Lift-off. The can barely missed my right eye, made an inverse crater in the ceiling, the smoldering innards landed on the carpet and I extinguished that with some piece of clothing. Needless to say my parents were pissed and my ego was back down, way down. After spackling and painting the ceiling I had to get a new carpet for my little room. Found a big enough chunk on sale but had to transport it home 5 miles on my bicycle. A very humbling experience.

--
Regards, Joerg

http://www.analogconsultants.com/

This part goes along that path without eliminating all the profit for the manufacturers.

Best regards, Spehro Pefhany

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"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Looks good, although 150kHz ain't much to write home about. And it seems (at this time) to be single-sourced.

Well, there wouldn't be so many mfgs for the 33063 if there wasn't a profit to be had.

--
Regards, Joerg

http://www.analogconsultants.com/

Where's a place to buy low quantities at cheap prices? I just checked DigiKey for the 1N916...36,000 minimum order.

And the prices on the op-amps being talked about are also a lot more than being quoted. 25 is a lifetime supply for me. mike

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Return address is VALID!

Biggest problem I'm having with the LM324 is that as the supply voltage goes down, the output swing and + end of the input common mode range gets severely squeezed. I'll look at the LMV324. thanks, mike

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Try here

1+for .024 cents

When it's down to single-cell performance I often migrate back to discrete designs. Opamps don't really cut it down there or are exotic respectively expensive.

--
Regards, Joerg

http://www.analogconsultants.com/

This ought to be cheap enough:

$0.03 if you buy one. If you want to splurge and order ten of them they'll drop to two cents a pop. Heck, you can't even buy a pack of Wrigley's for that anymore :-)

LMV358, 53 cents in single qty:

The LM324 can be had for 15 cents:

You'd have to check for the right housing depending on what you want, the Mouser web site is a bit clumsy in that respect.

--
Regards, Joerg

http://www.analogconsultants.com/

Mouser.

1.5 cents in Q100. They did pull a fast one on the shipping, though. Might want to stick with the priority mail method for small orders - they residential-ized my legitimate business shipping address, which added 43% to the shipping. The transistors, for no obvious reason, were somewhat cheaper in "ammo pack", even for onesies. I don't care how they are packed, so I bought 100 each that way.

Check Newark as well.

Always pays to shop around

- various things are wildly different (or available/not available) for no obvious reason.

Those are the three I start with. Others have suggested, but I have not dealt with:

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Cats, coffee, chocolate...vices to live by

On Wed, 30 Jan 2008 08:41:14 GMT, mike wrote:

:I've been designing hobby analog projects with the venerable :LM324 for longer than I care to think. My most recent databook is 1989. :But it's running out of steam. Power supply voltages are getting :lower etc. And I've lasted longer than my lifetime supply of 'em. : :What's the reigning jellybean quad op amp of the day? : :Looking for something like the LM324. Stable, low power, :dirt cheap, available everywhere, wide power supply voltage :range, but usable with a 3V single ended power supply, :rail to rail output and wide input common mode range that :includes ground. : :And be available in a package that a geezer :with a hand held soldering iron can hook up...dip/soic etc. :maybe a single-amp sot23 variant. :Seems like everything in the trade mags today is so small a gnat :could eat more than one. I'm not building cellphones, I'm hanging :together hobby stuff with real wires and low density home brew :single-sided circuit boards. Real designers need leaded packages... :not to be confused with packages containing lead...although I'd rather :have lead coated lead frames. ;-) : :Wide bandwidth is sometimes good...but the thing I liked best :about the LM324 is that you could just hook it up and it worked. :Pick any spec and it was good enough. Rarely even looked at the spec sheet. :I don't remember ever having one oscillate on me...even with caps :hanging directly on the inputs and/or outputs. A small amp is no :use if it takes a dozen passives to keep it stable. : :Would be nice to pick something that has a chance of being available a :decade from now. Hate to waste the few brain cells I have left learning :the idiosyncrasies of a new chip on every design. : :Recommendations for a LM324 replacement? :Thanks, mike

While I haven't yet used the MC34074 it looks like it could be a very capable replacement for the LM324.

However, for a single it's rather expensive.

--
Regards, Joerg

http://www.analogconsultants.com/

An MC34074 (TL074) is a quad... BUT it's NOT a low voltage part.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave

Sorry, had the 34071 in mind. Mea culpa. But the 34074 isn't that cheap either, almost 40c a pop versus