really, really stupid EDN stuff

That was submitted by an employee at Analog Devices? OMG, Jim Williams = and=20 Robert Pease are probably rolling in their graves. Then again, maybe = this=20 was the janitor?

That wasn't too bad except the claim of a gain of 1,000,000. And why = would=20 anyone want to make an op-amp from discretes, except as a science fair=20 project, or special purpose types (high voltage for example).

Paul=20

Discretion is the better part of voltage?

mike

Oh God. Popular Electronics had better stuff in the 70's. MUCH better stuff.

Does EDN still publish a printed magazine as well as the web?

I remember when I first saw EDN and McGraw Hill Electronics as a kid and thought it was so much better than PE.

I'm not too thrilled with the dots on the IC outline in the ADI circuit.

Seems to me that zener trick would make a noisy amplifier.

Hey, it's December. Those could possibly be the best circuits sumitted. I hope not, but who knows.

In the days when a freakin' PIC is the solution to everything, I can't complain too much about a submission of analog circuits. Granted, better circuits would be appreciated. But Jim or Bob would like these circuits way more than some Arduino app.

And since when is a single-ended AC amplifier an "op amp"?

That and the 48GHz gbw :)

NT

Everything's shorted! EDN makes drafting errors on most of the schematics they publish. What can you expect from journalism majors?

But aside from the several other stupidities, what's with the single-coil latching relay? It will pull in once and never drop out after that.

John

OMG! Another infinity! Bwuahahahaa!

Ever heard of a toggle mechanism? The second energization unlatches and resets the relay. Same way the stereo cabinet door latch works.

That's an optional feature. With that option, your dusk detector "remembers" that dusk was detected, even if there is a power failure. :-)

Ed

Got a link to an alternate action magnetic latching relay?

After you provide that, please explain how it would make sense in this application.

Or maybe you're just AlwaysWrong.

John

It can be resest with a mechanical shock, but reverse current is not an option with the protection diode.

Nobody said a damned thing about it latching by way of any magnetic action. You are simply just always an idiot... as usual.

The EDN article did.

Even if it worked some other way, how would an alternate-action relay make any sense here?

John

That triple cascade CE is no biggie, but as already mentioned, the zener is in the wrong place for noise attenuation, he doesn't have any loop gain in front of it except his external error amp, which I assume would be a necessity for a gain 120dB. The trick would be to finagle it to the last stage and not the first.

Late at night, by candle light, John Larkin penned this immortal opus:

What about the SOB (Shine Once, Briefly) LED and the 10k in series with the battery?

- YD.

It becomes a Darkness Emitting Diode (DED). And since its power is=20 unlimited, it creates a condition of eternal night until you turn it = off.

Paul=20

All "light sources" are really dark suckers.

I liked the 3 transistor op-amp when i saw it; a bit crazy - but that is my style..

circuit.

No. There are single coil mechanical versions which will alternate. Stitches also.

?-)